Abstract: Field efficacy test method was used to determine the effect of 40% Bispyribac-sodium SC on weeds in direct seeding rice field and to investigate the rice safety and the weeds control efficacy in the early season rice and late season rice field from 2012 to 2013 in south China. The results showed that the control efficacy on grasses weeds 也Echinochloa crusgalli (L.) Beauv, cyperaceae weeds (Cyperus difformis L., Cyperus iria L.) and annual broadleaf weeds Monochoia vaginalis(Burm.f.) significantly decreased by 26.25~30.0 g/hm2a.i.40% Bispyribac-sodium SC when the rice was in 3-4 leaf stage with spray processing. The rice was safety with the recommended dose, and there was no phytotoxicity with higher concentration.