Abstract: To develop low toxicity and environment-friendly botanical fungicide,the quaternary benzophenanthridine alkaloids(QBAs) was prepared with the method of acid extraction and alkali sink;the contents of sanguinarine and chelerythrine alkaloids in the QBAs were determined by high performance liquid chromatography(HPLC).Antibacterial activity of QBAs bisulfate was tested by mycelium growth rate method and pot growing method.The acute toxicity of QBAs bisulfate was tested.The results showed that,the mass fraction of sanguinarine and chelerythrine was more than 60% in the QBAs.The QBAs bisulfate displayed strong inhibition effects on Cercospora viticola,Elsinoe ampelina,Colletotrichum gloeosporioides,Cercospora viticola,Pyricularia oryzae,Gibberella zeae and Phytophythora capsici.The EC50 values were 3.35-10.08 μg/mL.The QBAs bisulfate showed low toxicity in acute oral,acute inhalation and acute dermal toxicity tests,no stimulating effect on the skin but weak sensitization and severe irritation to the eyes.In conclusion,the preparation method of QBAs from M.cordata is stable and reliable,and QBAs bisulfate exhibited strong antibacterial activity and low acute toxicity.