三个办法：
第一，如果程序自带选项(option)调整格式的话帮助文件里会说的。所以可以再参考一下帮助文件。
第二，可以考虑修改一下程序，通过自己编程改变输出格式。
第三，做表的时候自己在excel或者word里改一下。

Exporting results

    You can export your results with outreg2. Run the following command after diff with double difference:
        
    outreg2 using table_diff, ctitle(`r(depvar)') addstat(Mean control t(0), r(mean_c0), Mean treated t(0), r(mean_t0), Diff t(0), r(diff0), Mean control t(1), r(mean_c1), Mean
        treated t(1), r(mean_t1), Diff t(1), r(diff1)) label excel keep(_diff) nocons

    Run the following command after diff with triple difference:
        
    outreg2 using output, ctitle(`r(depvar)') addstat(Mean control - A t(0), r(mean_c0a), Mean control - B t(0), r(mean_c0b), Mean treated A - t(0), r(mean_t0a), Mean treated B
        - t(0), r(mean_t0b), Diff t(0), r(diff0), Mean ), r(mean_c1a), Mean control - B t(1), r(mean_c1b), Mean treated - A t(1), r(mean_t1a), Mean treated - B t(1),
        r(mean_t1b), Diff t(1), r(diff1)) label excel keep(_diff) nocons dec(4)

    Results will be stored in the working directory (also see help outreg2 for further options).