Abstract: Fish resources of lower mainstream of the Minjiang River were investigated four times between 2014 and 2016. A total of 71 fish species (and subspecies) were identified inside 3 orders, 11 families, and 51 genera, in which 16 species are endemic species of the upper Yangtze River. The similarity index analysis of fish composition from different river sections showed that the similarity between Yinbin and Leshan reaches was the lowest (7000%), whereas Yibin and Pinshan sections had the highest similarity index (9219%). The main economic fish species in the studied river sections included Cyprinus carpio、Pelteobaggrus nitidus and Pelteobagrus vachelli, and their percentages inside all captures were 1610%, 1396% and 1232% respectively. The 71 species fishes spawning type analysis showed the fish that producing sticky eggs and drifting eggs accounted 6828% and 2707% of the total weight of captures, respectively. Fish diversity index between may and July were obviously higher than that between October and December. The fish Pielou indexes of Leshan and Qianwei sections showed significantly difference (p < 005). Overall, our field investigations showed the lower mainstream of Minjiang River had high fish species richness and biomass, but the fishes resources may not be optimistic in the future due to several hydraulic power plants constructions, fishery resource protection should be strengthened soon.