The mosquito vector of filariasis malayi and its vectorial capacity was investigated In 5 endemic villages in Leshan Prefecture, Sichuan Province. The results showed that the man-biting rate, numan blood index and vectorial capacity of An. lesteri anthropophagus were 0.7, 5.1 and 10.63 times higher than those of An. sinensis. Besides, the natural infection by microfilaria in An, lesteri anthropophagus was also higher than that in An. sinensis by 5 times.From the above result, the authors concluded that An. lesteri anthropophagus was the main vector for transmitting filariasis malayi in the area under study.