An epidemic disease named“muscle emulsification disease” consecutively happened in cultured swimming crab Portuns trituberculatus during the years 2003 - 2004 in Zhousan, Zhejiang Province. This disease, with the symptoms of muscle shrink and emulsification, mainly occurred on temporarily cultured swimming crab in low water temperature from Oct. to Feb., caused serious loss. A great deal of yeast-like organism was observed from the milky emulsion in the leg, and with lid open, milky liquid was seen. as well as in muscle,heart, hepatopancreas from the disease crab. These yeast-like organism were isolated and cultured with TCBS agar and identified as Candida oleophila. Artificial challenge test showed that the isolated yeast could cause emulsification disease of health swimming crab, when injected or dipped with the cultured yeast, with the similar symptom as the naturally infected crab. oleophila was re-isolated from the artificial infected crab. The results showed that Candida oleophila was the pathogen of the muscle emulsification disease of swimming crab in Zhejiang Province in recent years.