Abstract: The pathogen of bean Sclerotinia rot was purified from greenhouse in TianJin.The morphology characteristics and pathogenicity and biological characteristics of the pathogen were studied. The results showed that Sclerotinia sclerotiorum (Lib) de Bary.was identified as pathogen. The temperature for colony growth ranged from 5~30℃and the optimum growth temperature ranged from 18~23℃;The optimum growth humidity for colony growth ranged from 90%~100%;Among the tested carbon and nitrogen souses,lactose was useful types,ammonium sulphate was the favorable nitrogen source for mycelium growth;Mycelium could grow at pH 3~10,with the optimum 6.5.