Abstract: In order to enhance the occupation ratio of aquaculture tanks in workshop construction and take into account the better flow field performance of aquaculture tanks, it is necessary to determine the appropriate length-width ratio parameters of aquaculture tanks.In this paper, the Computational Fluid Dynamics technology is used to numerically simulate the flow field characteristics of rectangular circular Angle aquaculture tanks with different L/W (the ratio of the length L of the long side and the side L of the wide side and the side W of the aquaculture tanks).For straight double tube (two inlet pipe layout in the adjacent straight wall middle position) inflow of three-dimensional turbulent flow numerical model, the breeding and feed line layout at the edge of the long and wide edge, comparing the two kinds of working condition of calculation analysis of two kinds of working condition of flow velocity in the breeding, resistance coefficient, water uniformity, vorticity flow field, such as evaluation indexes. The results showed that the variation trend of flow field with the change of aspect ratio was basically the same in the two working conditions. L/W maintained good flow field performance in the range of 1.0 to 1.2, L/W sharply decreased in the range of 1.2 to 1.6, and L/W had poor flow field performance in the range of 1.6 to 1.9. The results can provide a basis for the design and optimization of flow field performance of industrial recirculating aquaculture tanks.