Abstract:To identify and select the active compounds which have antifungal activities on Penicillium digitatum, the growth rate and the binding-spectroscopic analysis was used to evaluate the antifungal activities and the binding capacity of fungicide with P.digitatum CYP51 about two triazole fungicides and four new nitrogen compounds. The results showed that 7-methoxy-2H-benzothiazin-3-amine displayed strong antifungal property, and the EC50 was 1.18mg/L which was close to the diniconazole (0.09mg/L); and moderate antifungal effects were observed with the other three nitrogen compounds with the EC50 of 7.88, 10.09, 38.56mg/L, respectively. Different compounds had different binding capacities with heterologous expression of CYP51 in citrus green mold. There is a positive correlation between antibacterial activity of compounds and the ability of compounds combined with CYP51. Analysis of structure-activity relationship showed that the introduction of sulfur may increase the capacity of compounds to suppression of green mold.