控制此操作的默认样式位于ListItem中，其中指定了justifyContent：“灵活启动”。
您可以将其更改为右对齐：

const MenuItem = withStyles({
  root: {
    justifyContent: "flex-end"
  }
})(MuiMenuItem);

下面是一个完整的工作示例：

import React from "react";
import Button from "@material-ui/core/Button";
import Menu from "@material-ui/core/Menu";
import MuiMenuItem from "@material-ui/core/MenuItem";
import { withStyles } from "@material-ui/core/styles";

const MenuItem = withStyles({
  root: {
    justifyContent: "flex-end"
  }
})(MuiMenuItem);

export default function SimpleMenu() {
  const [anchorEl, setAnchorEl] = React.useState(null);

  const handleClick = event => {
    setAnchorEl(event.currentTarget);
  };

  const handleClose = () => {
    setAnchorEl(null);
  };

  return (
    <div>
      <Button
        aria-controls="simple-menu"
        aria-haspopup="true"
        onClick={handleClick}
      >
        Open Menu
      </Button>
      <Menu
        id="simple-menu"
        anchorEl={anchorEl}
        keepMounted
        open={Boolean(anchorEl)}
        onClose={handleClose}
      >
        <MenuItem onClick={handleClose}>1</MenuItem>
        <MenuItem onClick={handleClose}>2</MenuItem>
        <MenuItem onClick={handleClose}>3</MenuItem>
        <MenuItem onClick={handleClose}>10</MenuItem>
        <MenuItem onClick={handleClose}>20</MenuItem>
        <MenuItem onClick={handleClose}>300</MenuItem>
      </Menu>
    </div>
  );
}

相关文件：

• https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content
• https://css-tricks.com/snippets/css/a-guide-to-flexbox/

更灵活地解决您的问题，
在<MenuItem>中使用<ListItemText>这样你就可以对元素的一部分设置样式。

<MenuItem onClick={handleClose}>
      <ListItemText style={{ paddingRight: 50 }}>undo</ListItemText>
      <ListItemText style={{ textAlign: "right" }}>ctrl+z</ListItemText>
    </MenuItem>

例如：shortcut hint on the right。

您可以使用以下代码对齐菜单

anchorOrigin={{
  vertical: 'bottom',
  horizontal: 'center',
}}
transformOrigin={{
  vertical: 'bottom',
  horizontal: 'center',
}}

示例

<Menu
 id="order-menu"
 anchorEl={anchorEl}
 keepMounted
 open={Boolean(anchorEl)}
 onClose={() => setAnchorEl(null)}
 anchorOrigin={{
   vertical: 'bottom',
   horizontal: 'center',
 }}
 transformOrigin={{
   vertical: 'bottom',
   horizontal: 'center',
 }}
 style={{top: 170}} // you can set top position so that it will show under the selection
>
 {options.map((option, index) => (
   <MenuItem
     key={option}
     selected={index === selectedIndex}
     onClick={(event) => handleMenuItemClick(event, index)}
   >
     {option}
   </MenuItem>
 ))}

MUI5可以使用SX。

<MenuItem sx={{ justifyContent: 'flex-end' }}>