In view of the lack of quantitative analysis on the alternative habitatsuitability and influencing factors in the Luosuo River, Tor sinensis, a unique economic fish in the main stream of the Lancang River, was selected as the target species, and the habitat evaluation model of typical fish in theLuosuoRiver was established based on the intra-river flow increasing method(IFIM), two-dimensional hydrodynamic model and fish habitat suitability curve. The alternative habitat suitability and its influencing factors were analyzed. The results show that the Luosuo River, as the largest tributary of Langcang River, can provide a good spawning ground for Tor sinensis. The number and quality of spawning ground are better in wet season(July to September), and high-quality spawning ground is mainly distributed in the meandering part of the river. The tributaries of the Luosuo River are not suitable for adult fish to inhabit all year round, especially in the dry season(February to April), and the suitability of adult fish for spawning and fattening is the worst in this period. In the later management of the alternative habitat of the Luosuo River, it is recommended to give priority to strengthening the habitat protection and fishing management at the river bend, and pay attention to the ecological protection of its associated mainstreamat the same time.