Abstract: Mixing propisochlor with atrazine is one of efficacious methods that can reduce phytotoxicity of triazine herbicides on maize. The experiment with mixture of propisochlor and atrazine to control weeds(Digitria sanguinalis, Setaria faberii,Portulac oleracea) was carried out at laboratory. The results showed that the co-toxicity coefficient of propisochlor and atrazine was higher than 100 when their mass-ratio was 18∶23 (prescription B). The main technical index of suspo-emulsion of prescription B accorded with professional standard such as the rate of suspension, dumping and quality stability.