Chicken anemia virus (CAV)， the causative agent chicken anemia， is the only member of the genus Gyrovirus of the Circoviridae family. CAV is an immune suppressive virus and causes anemia， lymph organ atrophy and immunodeficiency. The production and biochemical characterization of VP1 protein and its use in a subunit vaccine or as part of a diagnostic kit would be useful to CAV infection prevention.