The pot experiment was carried out for 26.5% mefenacet o bensulfuron methyl SC and 53% mefenacet o bensulfuron methyl WP.The reproductive traits of rice,i.e.,plant height,the number of tiller,the effective number of spike,yield,and the controlling effect to barnyard grass were analyzed.The results showed that compared with mefenacet o bensulfuron methyl WP,mefenacet o bensulfuron methyl SC reduced the amount of pesticides without a significant reduction for the control to barnyard grass and it was safe for rice at the same time.