In order to improve the hydrodynamic conditions of aquaculture tank and reduce the energy consumption of industrial recirculating aquaculture, a three-dimensional numerical calculation model of aquaculture tank with water inlet on straight wall double pipe (two inlet pipes arranged in the middle of two non-adjacent straight walls) was established by using computational fluid dynamics (CFD) technology, and the flow field characteristics in the square arc angle aquaculture tank with different jet angles were simulated numerically. The results show that the jet angle has obvious influence on the average velocity and the uniformity of flow field distribution in the aquaculture tank. Under the same cycle number setting condition, when the jet angle is between 0 ° and 10 °, it is conducive to obtain higher water velocity and more uniform flow field. Especially when the jet angle is 0 °, the effect is the best, and the flow field characteristics in the aquaculture tank are better than those under other working conditions, which can meet the needs of reducing the energy consumption of aquaculture and constructing a suitable flow field for breeding creatures. This study can provide a reference for the design and construction of flow field in the industrial recirculating aquaculture system.