In order to learn about the host diversity and distribution pattern of Trichodina heterodentata Duncan, 1977, the morphological and biodiversity statistical survey method were used to investigate the host diversity and geographic distribution of T. heterodentata. The research results indicated that the hosts of T. heterodentata included fishes and amphibians (juvenile), and fishes were the primary hosts for T. heterodentata. Among the fish hosts, the Perciformes fishes were up to 34 species, and the host dominant index (Y=0.38) was the highest. The parasitical localities included gills, skin and fins, and the gill-parasitism was the primary parasitical way for host fishes. However, the skin-parasitism was the primary parasitical way for host amphibians. With respect to the study of geographic distribution, for the six fauna realms, distribution of T. heterodentata was found in five ones except Nearctic realm. Among them, Neotropical realm has the highest host diversity, and Oriental realm has the lowest one. For the seven continents of the world, South America has the highest host diversity, and Asia has the lowest one. The Chi-Square test result indicated that the distribution of T. heterodentata was closely related to difference of fauna realms (χ2=93.138，p<0.01) and continents (χ2=80.925，p<0.01) of the world. In China, T. heterodentata has rich host diversity with about one fourth of the world’s species, and is concentrated in North China, Central China and South China. Among them, South China is the widest distribution area for T. heterodentata. In terms of the river system, T. heterodentata is distributed in systems of Yangtze River, Hai River and Pearl River, and Pearl River takes pole position in China. In terms of provinces and districts, more than ten host species are only distributed in Taiwan and Guangxi area, and Taiwan possesses the most host species in China. The above results indicate that T. heterodentata had a high host diversity, and the fish was its primary host. Among the fish hosts, the Perciformes fishes were the dominant host. In the geographical distribution of the world, regions near the equator (Neotropical zone/South America) were of the highest host diversity for T. heterodentata. In China, T. heterodentata was mainly distributed in the southern or southern regions of our country.