1、使用hhline宏包\documentclass{article}\usepackage{hhline} % 双线表\begin{document}\begin{tabular}{r|r||r|r||r|r||r|r}\hline $n$&$I_n$&$n$&$I_n$&$n$&$I_n$&$n$&$I_n$\\\hhline{--||--||--||--} 19&0.008\ 3&14&0.011\ 2&9&0.016\ 9&4&0.034\ 3\\ 18&0.008\ 9&13&0.012\ 0&8&0.018\ 8&3&0.043\ 1\\ 17&0.009\ 3&12&0.013\ 0&7&0.021\ 2&2&0.058\ 0\\ 16&0.009\ 9&11&0.014\ 1&6&0.024\ 3&1&0.088\ 4\\ 15&0.010\ 5&10&0.015\ 4&5&0.028\ 5&0&0.182\ 3\\\hline\end{tabular}\end{document}
2、\documentclass{article}\usepackage{ctex}\usepackage{tabularx}\newcolumntype{Y}{>{\centering\arraybackslash}X}\usepackage{hhline} % 双线表\usepackage{makecell} %\makecell命令可以单独控制表项单元，可以在表项中使用\\命令换行；\Xcline{起-止}{线宽}；\Xhline{线宽}\newcommand{\tabincell}[2]{\begin{tabular}{@{}#1@{}}#2\end{tabular}} %\tabincell{c}{}%换行\begin{document}\begin{tabularx}{\textwidth}{c|c|Y||c|c|Y}\hline%\Xhline{0.9pt}企业编号& 产量(台)&\tabincell{c}{生产费用\\[-1mm](万元)}&企业编号&产量(台)&\tabincell{c}{生产费用\\[-1mm](万元)}\\\hhline{---||---}%\Xcline{1-3}{0.6pt}\Xcline{4-6}{0.6pt}1& 40& 130&7& 84& 165\\2& 42& 150&8& 100& 170\\3& 50& 155&9& 116& 167\\4& 55& 140&10& 125& 180\\5& 65& 150&11& 130& 175\\6& 78& 154&12& 140& 185\\\hline%\Xhline{0.72pt}\end{tabularx}\end{document}
