Kiwi brown spot is one major disease in Sichuan kiwifruit production areas in recent years, which occurs in mid-to-late of June and widely spreads in mid-to-late of July, and the diseased leaf rate nearly reaches 50% ~ 80% in most of production orchards in Sichuan.In this paper, the sporulation condition of the causal agent Corynespora sp.was optimized, and the pathogenesis of synthesized toxin was analyzed.Pathogenicity test of eight pathogenic isolates from the infected leaves in different disease sites showed that strain CQ2-0 from Qionglai had the strongest pathogenicity.