是不是在plot()令axes=FALSE
然后在box()就可以啦？

axes=FALSE 是禁止坐标轴的生成用——
xaxt="n", yaxt="n"

R环境内部help的解释
xaxt/yaxt
A character which specifies the x/y axis type.
Specifying "n" suppresses plotting of the axis. The standard value is "s": for compatibility with S values "l" and "t" are accepted but are equivalent to "s": any value other than "n" implies plotting.