In order to improve the hydrodynamic conditions in the aquaculture tanks and the self-cleaning capacity of the aquaculture tanks, a dual channel drainage system was used to achieve the first effective separation of solid waste in the aquaculture tanks, and the flow field characteristics in the dual channel aquaculture tanks were studied. Based on computational fluid dynamics (CFD) technology, the three-dimensional turbulent numerical model of rectangular arc angle aquaculture tanks was established in this paper, and the flow field characteristics of single channel and dual channel aquaculture tanks were compared and analyzed. The results show that in the case of single-tube inflow, the average velocity in dual channel aquaculture tanks was about 7% higher than that of single channel aquaculture tank, the resistance coefficient was about 13% lower and the uniformity coefficient UC50 was about 23% higher greatly. While in the case of double-tube inflow, the average velocity in dual channel aquaculture tanks was about 8% higher than that of single channel aquaculture tank, the resistance coefficient was about 14% lower and the uniformity coefficient UC50 was about 7% higher. The results indicate that the underflow split ratio in the dual channel aquaculture tanks has little effect on the flow field characteristics, and the dual channel drainage system can effectively improve the hydrodynamic conditions in the aquaculture tank and enhance the hydraulic mixing characteristics.