To investigate the pathogenicity of avian influenza virus in Gerbil Anesthetized gerbils were inoculated with avian influenza virus in biosafety level 3 laboratory. Fourteen days after inoculation,clinical signs were observed and the blood samples were collected to analyze abti-AIV antibody. Tissue samples from lungs, livers, and kidneys were used to virus isolation and histopathology. Result showed that the H5N1 AIV caused severe disease in gerbils mainly between day 2.p.i ang 6.p.i, which characterized by ruffled fur, inappetence, hunched-back posture, labored breathing, hypothermia, weight loss. The death rate was 44%. Antibody was detectable from day 10. P.I. The histopathologic examinations showed variable degrees of lesions including congestion and hemorrhage in lungs, livers, kidneys. The lesions of the lungs showed interstitial pneumonia, dropsy and configuration breakage.