Taking Corynespora cassiicola （Berk. & Curt.）Wei. as pathogen，allied toxicity measurement in laboratory and field control efficacy trial on famoxadone·mancozeb were conducted．The results showed that EC50 of famoxadone·mancozeb and mancozeb were 1.16 mg·L^-1and 6.23 mg·L^-1，respectively. The results of field trial indicated that after 3 successive applying of 68.75% famoxadone·mancozeb WG at 468.0，625.5，and 937.5 g·hm^{- 2} dosages，the control efficacies on Corynespora cassiicola could reach 78.61%，89.33% and 90.28%，respectively. Under these concentrations，no side effect was observed on cucumber.