基于https://bookdown.org/yihui/rmarkdown-cookbook/reuse-chunks.html的解决方案：

---
title: plot now, render later
output: html_document
---

We put some plot expression here to evaluate it later:
```{r, deja-vu, eval=FALSE}
x = 1
plot(x)

Here we change x - but only within the corresponding chunk's scope:

x = 10

... moving on

Here, we evaluate and plot the expression defined earlier; x is taken from that chunk's scope, so it still evaluates to 1:

![](https://i.stack.imgur.com/JRuJJ.jpg)

一个选项是使用ggplotify中的as.grob函数将绘图保存为grob对象，然后在其他地方打印。

---
title: "Saving A Plot"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)

R Markdown

library(ggplotify)
library(grid)

show_captured_plot <- function(grb) {
  grid::grid.newpage()
  grid::grid.draw(grb)
}

x <- 1

p <- as.grob(~plot(x))

Now we can plot the figure here.

x <- 10

show_captured_plot(p)

![](https://i.stack.imgur.com/Bie2I.png)

在这里，查看以下链接：https://bookdown.org/yihui/rmarkdown-cookbook/fig-chunk.html
它有很多关于如何开始使用rmarkdown的说明。
明确回答你的问题：
我们在此代码块中生成一个图，但不显示它：

```{r cars-plot, dev='png', fig.show='hide'}
plot(cars)

又过了一段，我们介绍剧情：

![A nice plot.](r knitr::fig_chunk('cars-plot', 'png'))

基本上，您必须将图形保存为变量，然后使用`knitr::fig_chunk()`函数调用它。