你可以使用下面的css来使它在没有选中的时候变成红色，选中的时候变成黑色

.custom-control-label:before{
  background-color:red;
}
.custom-checkbox .custom-control-input:checked~.custom-control-label::before{
  background-color:black;
}

可以通过下面的代码更改箭头的颜色

.custom-checkbox .custom-control-input:checked~.custom-control-label::after{
  background-image:url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3E%3Cpath fill='red' d='M6.564.75l-3.59 3.612-1.538-1.55L0 4.26 2.974 7.25 8 2.193z'/%3E%3C/svg%3E");
}

这段代码会使勾号变成红色，你可以通过改变fill='red'的值来改变颜色。
编辑：注意，如果指定RGB颜色，例如#444444，则使用%23作为散列，例如%23444444
或者你可以使用任何你喜欢的图片。

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.3/css/bootstrap.min.css" integrity="sha384-Zug+QiDoJOrZ5t4lssLdxGhVrurbmBWopoEl+M6BdEfwnCJZtKxi1KgxUyJq13dy" crossorigin="anonymous">

<style>
    .custom-control-label:before{
        background-color:red;
    }
    .custom-checkbox .custom-control-input:checked~.custom-control-label::before{
        background-color:black;
    }
    .custom-checkbox .custom-control-input:checked~.custom-control-label::after{
        background-image:url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3E%3Cpath fill='red' d='M6.564.75l-3.59 3.612-1.538-1.55L0 4.26 2.974 7.25 8 2.193z'/%3E%3C/svg%3E");
    }
    .custom-control-input:active~.custom-control-label::before{
        background-color:green;
    }
   
    /** focus shadow pinkish **/
    .custom-checkbox .custom-control-input:focus~.custom-control-label::before{
        box-shadow: 0 0 0 1px #fff, 0 0 0 0.2rem rgba(255, 0, 247, 0.25); 
    }
</style>  

<div class="custom-control form-control-lg custom-checkbox">  
    <input type="checkbox" class="custom-control-input" id="customCheck1">  
    <label class="custom-control-label" for="customCheck1">Check this custom checkbox</label>  
</div>

编辑：在@cprcrack的请求后添加了焦点颜色（粉红色）

我想在这里添加一个比knetsi的答案更简单和更通用的答案，对于那些可能对:checked伪类的颜色变化不感兴趣的人来说。
我只是想定义一个类my-error，我可以在复选框中添加或删除它来改变它的颜色，在本例中是为了反映错误条件。
下面是它在代码中的样子：

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css" integrity="sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B" crossorigin="anonymous">

<style>
  .custom-checkbox .custom-control-input.my-error~.custom-control-label::before{
    background-color:orangered;
  }
</style>

<div class="custom-control custom-checkbox">
  <input type="checkbox" class="custom-control-input my-error" id="customCheck1">
  <label class="custom-control-label" for="customCheck1">Check this custom checkbox</label>
</div>

编程环境Angular 10.0
预览-x1c 0d1x
HTML

<!-- BLUE CHECKBOX -->
<div class="custom-control custom-checkbox">
  <input type="checkbox" [checked]="true" class="custom-control-input" [id]="['chk-add',item.id,uniqueTag].join('-')" />
  <label class="custom-control-label" [for]="['chk-add',item.id,uniqueTag].join('-')"></label>
</div>
<!-- GREEN CHECKBOX -->
<div class="custom-control-products custom-checkbox-products">
  <input type="checkbox" [checked]="true" class="custom-control-input-products" [id]="['chk-add',item.id,td.id,uniqueTag].join('-')" />
  <label class="custom-control-label-products" [for]="['chk-add',item.id,td.id,uniqueTag].join('-')"></label>
</div>

SCSS / CSS

.custom-control-products {
    position: relative;
    display: block;
    min-height: 1.5rem;
    padding-left: 1.5rem;
  }

  .custom-control-input-products {
    position: absolute;
    left: 0;
    z-index: -1;
    width: 1rem;
    height: 1.25rem;
    opacity: 0;
  }
  
  .custom-control-input-products:checked ~ .custom-control-label-products::before {
    color: #fff;
    border-color: #007bff;
    background-color: #007bff;
  }
  
  .custom-control-input-products:focus ~ .custom-control-label-products::before {
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
  }
  
  .custom-control-input-products:focus:not(:checked) ~ .custom-control-label-products::before {
    border-color: #80bdff;
  }
  
  .custom-control-input-products:not(:disabled):active ~ .custom-control-label-products::before {
    color: #fff;
    background-color: #b3d7ff;
    border-color: #b3d7ff;
  }
  
  .custom-control-input-products[disabled] ~ .custom-control-label-products, .custom-control-input-products:disabled ~ .custom-control-label-products {
    color: #6c757d;
  }
  
  .custom-control-input-products[disabled] ~ .custom-control-label-products::before, .custom-control-input-products:disabled ~ .custom-control-label-products::before {
    background-color: #e9ecef;
  }
  
  .custom-control-label-products {
    position: relative;
    margin-bottom: 0;
    vertical-align: top;
  }
  
  .custom-control-label-products::before {
    position: absolute;
    top: 0.25rem;
    left: -1.5rem;
    display: block;
    width: 1rem;
    height: 1rem;
    pointer-events: none;
    content: "";
    background-color: #fff;
    border: #adb5bd solid 1px;
  }
  
  .custom-control-label-products::after {
    position: absolute;
    top: 0.25rem;
    left: -1.5rem;
    display: block;
    width: 1rem;
    height: 1rem;
    content: "";
    background: no-repeat 50% / 50% 50%;
  }
  
  .custom-control-input-products:checked ~ .custom-control-label-products::before {
    color: #fff;
    border-color: #007bff;
    background-color: #17a2b8a8 !important;
  }

  .custom-checkbox-products .custom-control-label-products::before {
    border-radius: 0.25rem;
  }
  
  .custom-checkbox-products .custom-control-input-products:checked ~ .custom-control-label-products::after {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' width='8' height='8' viewBox='0 0 8 8'%3e%3cpath fill='%23fff' d='M6.564.75l-3.59 3.612-1.538-1.55L0 4.26l2.974 2.99L8 2.193z'/%3e%3c/svg%3e");
  }
  
  .custom-checkbox-products .custom-control-input-products:indeterminate ~ .custom-control-label-products::before {
    border-color: #007bff;
    background-color: #007bff;
  }
  
  .custom-checkbox-products .custom-control-input-products:indeterminate ~ .custom-control-label-products::after {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' width='4' height='4' viewBox='0 0 4 4'%3e%3cpath stroke='%23fff' d='M0 2h4'/%3e%3c/svg%3e");
  }
  
  .custom-checkbox-products .custom-control-input-products:disabled:checked ~ .custom-control-label-products::before {
    background-color: rgba(0, 123, 255, 0.5);
  }
  
  .custom-checkbox-products .custom-control-input-products:disabled:indeterminate ~ .custom-control-label-products::before {
    background-color: rgba(0, 123, 255, 0.5);
  }