Cloransulam-methyl WDG, a kind of sulfonamide, is a effective herbicide to control broadleaf weedsin soybean field. The objective of this study was to determine its control effect to Commelina communis and its safe-ty to different soybean varieties. The results of field trial showed that cloransulam-emthyl 84% WDG at 25.2~50.4g a.i/hm² was an effective herbicide to C. communis. and the control effects was from 95.1% to 100% after 45 days.It was safety to ‘Jiyu57’, ‘Jiyu64’, ‘Jiyu70’ and ‘Jiyu74’, which showed no any phytotoxicity and it had no anyadverse effects to soybean growth stage and yields.