Abstract: In order to explore the application of bio-liquid in agricultural production and preservative development, Gas chromatograph mass spectrometer was used to analyze the chemical composition of bio-liquid, Colletotrichum nigrum was used as experimental strain, antibacterial experiment of bio-liquid and chitosan on Colletotrichum nigrum were experimented by growth rate method, and the interation between bio-liquid and chitosan was determined by the co-toxity factor method.The results showed that EC₅₀ of bio-liquid and chitosan on Colletotrichum nigrum were 50 times and 0.7 g/L. The minimum inhibitory concentration of biomass pyrolysis liquid on Pepper Anthracnose ( MIC) and minimum bactericidal concentration ( MFC) were 32.5 times and 29 times.Bio-liquid and chitosan mixed in different proprotions has synergistic effect, bio-liquid and chitosan EC₅₀ solution mixed by 1∶ 1 ratio has the largest co-toxicity factor.