Abstract: The antimicrobial activities of Chitosan biguandine hydrochloride (CGH) against S. Aureus, E. Coli and Rhizoctonia solani Kuhn were studied, respectively. Cherry tomatoes mass-loss ratio, firmness, total soluble solid, VC content, film penetration ratio and soluble acid content was examined attentively after fresh-keeping process with CGH as coating film. The minimal inhibited concentrations (MIC) against S. Aureus and E.Coli were 0.31 and 0.62mg/mL, respectively. CGH at 2.00mg/mL had a total antifungal effect on Rhizoctonia solani Kuhn. CGH with concentration of 3% coated on the cherry tomatoes showed a better preservation effect after 12d storage under (28±2) ℃. The mass-loss, firmness, total soluble solid, VC content, film penetration ratio and soluble acid content were 7.5%, 21.121N/cm2, 7.2%, 21.70mg/100g FW (fresh weight) , 27.4% and 0.35%, respectively.