Abstract: This article constructed a habitat suitability evaluation index system that consisted of flow velocity, water depth, water surface width, wetted perimeter and wetted area in Dadu River Basin. The construction of this system was based on the habitat environmental requirements of indicative fish. We selected four representative rivers in the upstream of Dadu River and then set up an empirical relationship formula between river flow and each habitat index. Then we determined the minimum appropriate flow standard for indicative fishes in different living periods and calculated the minimum appropriate ecologic flow for satisfying different habitat standards. The results show the minimum ecologic flow in nonavoid winter period in Zumuzu River is 183-785 m3/s, and 66 m3/s in avoid winter period. The minimum ecologic flow in nonavoid winter period in Dajin River is 266-865 m3/s, and 266 m3/s in avoid winter period. The minimum ecologic flow in Suomo River is 283 m3/s for the whole year. The minimum ecologic flow in nonavoid winter period in Cuosijia River is 319-382 m3/s, and 319 m3/s in avoid winter period. The determination of regional minimum ecologic flow could provide reference for indicative fish protection in the study area, maintain the regional ecological balance, and coordinate ecological environment and social development.