Abstract:During the parasite investigation of fishes along the area of Taihu Lake, China, three populations of Trichodina heterodentata Duncan, 1977 parasites on Channa argus, Odontobutis obcurus and Micropterus salmoides respectively were obtained in our work. By applying the internationally standard evaluation method and descriptive method, the SPSS statistical software was for the first time used to conduct the difference test on the three populations. The result indicates that the intra-specific differences are in existence despite possessing typical morphological structure and stable statistical data for T. heterodentata. Meanwhile, the present study of population comparison for T. heterodentata revealed that the host was not the cause for difference in denticle variety, but may influence the parasite's body size. Besides, the two hosts, Odontobutis obcurus and Micropterus salmoides, are the new host records for Trichodina heterodentata in the present work