查询百度之后，发现在R上一次显示多张图的函数很多，比如layout()或者分屏函数，但是这些都不是我想要的结果。
之后，发现了line()函数可以保留原来图片继续作图，在括号中填入所需画图的部分即可（我是将一个矩阵作图）。
先运行plot()函数，再注释掉plot()函数运行line()函数即可。
效果如下：
补充：R语言：在同一张图作不同曲线
R语言将两条曲线作在同一张图的方法是
library(ggplot2)
year<-c(1993,1998,2003,2008)
Res<-c(0.0227,0.0198,0.0155,0.0147)
COPD<-c(0.0138,0.0125,0.0075,0.0069)
#R语言基础包作图
plot(year,Res,col=2,type="b",ylim=c(0.005,0.035),xlab = "Year",ylab ="Morbidity")
lines(year,COPD,col=3,type="b")
legend("topright",pch=c(15,15),legend=c("Respiratory","COPD"),col=c(2,3),bty="n")
#ggplot包作图
dd <- data.frame(year,Res,COPD)
ggplot()+geom_line(data = dd,aes(x = year,y = Res,colour = "Respiratory"),size=1)+
geom_point(data = dd,aes(x = year,y = Res,colour = "Respiratory"),size=3)+
ylim(0.005,0.025)+
geom_line(data = dd,aes(x = year,y = COPD,colour ="COPD"),size=1) +
geom_point(data = dd,aes(x = year,y = COPD,colour = "COPD"),size=3)+
scale_colour_manual("",values = c("Respiratory" = "red","COPD" = "green"))+
xlab("Year")+ylab("Morbidity")+
theme(text=element_text(size=13, family="Comic Sans MS"))
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。
