Haemocytes were collected from Oncomelania hupensis snails by using tissue disruption and filtration method, stained by Giemsa and methylene blue, respectively, and observed under microscope. Number of haemocytes from one snail was counted. Out of 54 haemocytes, 3 types of cells were found: big round cells with particles, small round cells with oval nuclei and spindle cells with oblong nuclei. The diameter of big round cells with particles and small round cells with oval nuclei was (21.59-31.97) and (13.24-20.77) microm, respectively. Spindle cells with oblong nuclei was about (17.60-25.47) microm x (27.19-30.25) microm. The nucleocytoplasmic ratio of the above three type cells was 0.38, 0.44 and 0.38, and occupied 35.95% (19/54), 12.42% (28/54) and 51.63% (7/54), respectively. About 194 600 haemocytes were filtered from one single snail. It means that this filtration method is an effective one to extract haemocytes from O. hupensis.