+++ iromise [Oct 16 17 19:39 ]:
>   Thanks a lot, but If there is any way to to make the column width fixed
>   and at the same time transform markdown table to rst table correctly
>   without adding space?
>   If I make the column too large, the table in the web page(I use sphinx
>   to generate html) seems not friendly since we have to scroll the bar to
>   see more content...

You could insert spaces into the content.
This would allow pandoc to break the lines to fit them
in the fixed-width cells.