Abstract: 　AIM: To explore the relationship between the infection of the intermediate hosts of Paragonimus and their ecological environment.METHODS:Three different villages in Fujian Province were chosen to conduct the study.The infection of snails and crabs were surveyed.RESULTS:① In Ningyang Village, Wuyi mountain(stream type),the infection rate of the Potamon crabs (723.9/each) in section Ⅰ(rapid stream) was 5 times higher than that in section Ⅱ(rapid stream) 142.6/each. ② In Xikou Village, Mingching county( ditch type): The infection rate of the snails (Semisulcospira libertina ) to cercaria and the Potamon crabs were 4.2% and 1 738.3/each, respectively in 1996, being 28.9 and 8.5 times higher than those ( 0.2% and 204.7/each) in 1982.③ In Jishang Village, Jianou City,the infection rate of the snails ( Tricula ) and the Potamon crabs were 4.3% and 355.4/each respectively in ditch Ⅲ, 4.3 and 8.3 times higher than those (1% and 42.9%/each) in ditch Ⅱ.CONCLUSION: P.westermani distributed along the stream system, usually concentrating in the small, slow-running water bodies of the stream. P.skrjabini distributed in still smaller water bodies.The environment suitable for the breedings of the snails and crabs are also the suitable places for Paragonimus parasites to complete their life cycles.

Key words: Paragonimus, snail, crab, host, small ecological environment