The body shape, swimming speed, and tolerance ability to flow of fish are the evolution results of their long-term adaptation to the external aquatic environment. Under the action of swimming or water flow, fish and fluid will have complex interactions, resulting in a large amount of energy consumption, which has an important impact on their survival and growth. In this paper, rainbow trout was taken as the research object, and a three-dimensional numerical model based on physical size was constructed. The physical model was made by 3D printing, and the hydrodynamic characteristics were studied by flume experiment and numerical simulation. The results showed that in the Reynolds number range of 1.6 × 105 ~ 5.8 × 105, the fish resistance coefficient CX increased from 0.027 to 0.599 with the increase of impact angle, showing an exponential growth trend of inclinations in the range of 0° ~ 45°, and the lateral force coefficient CY showed a linear growth trend with the increase of inclinations, reaching the maximum of 0.71. Since the inclinations and the structural curvature of the fish have a synergistic effect on the flow velocity distribution around the fish, with the increase of the inclinations, the high-velocity area and the low-velocity area have a certain movement rule in the velocity field With the change of inclinations, different pressure distributions appear in different parts of fish, with the increase of the impact angle, the proportion of the positive pressure area on the stoss side increased from 23.90 % to 71.66 %, and the proportion of the positive pressure area on the slip slope decreased from 23.90 % to 1.35 %. The results can provide a reference for individual and group behaviors of rainbow trout, selection of breeding waters, development of breeding technology and equipment, and bionics research.