Abstract: In order to clarify the occurrence and epidemic rule of Parkin's disease in shellfish, we investigated the infection of parasitic protozoa (Perkinsus spp.) on the common shellfish hosts along the coastal area of Guangxi Province, and studied the epidemiology of Perkinsus spp. on two locally cultured bivalves (Crassostrea hongkongensis and Ruditapes philippinarum). The results show that among the 14 investigated shellfish species, 13 were infected by P. olseni, 8 by P. beihaiensis, and 7 by P. olseni and P. beihaiensis at the same time (the same type of shellfish was at most infected with one kind of parasitic protozoa). The prevalence of P. olseni in Soletellina acuta, Callista erycina, R. philippinarum and Scapharca subcrenata was significantly higher than that in the other 10 species. The prevalence of P. beihaiensis in C. hongkongensis and Perna viridis was significantly higher than that in the other 12 species. The prevalence of P. beihaiensis was significantly higher than that of P. olseni in C. hongkongensis. The prevalence of P. olseni was significantly higher than that of P. beihaiensis in R. philippinarum. The prevalence of Perkinsus spp. varied in different shellfish species and coastal areas.