In order to study the influence of the inlet jet spacing of the culture pond on the flow field characteristics in the square arc-angle culture system under the double-tube jet mode (the jet position is at the arc-angle and the jet angle is 30°), a three-dimensional numerical calculation model was constructed by using the finite volume method and the finite difference method with the fluid dynamics simulation technology. The RNG k-ε turbulence model was used to simulate the flow field in the factory recirculating culture pond. The results show that the optimization of inlet jet spacing can effectively improve the overall flow velocity, the uniformity of flow field distribution and the effective utilization coefficient of energy in the culture pond, reduce the energy loss of inlet jet and improve the economic benefit of sewage discharge. When the inlet jet spacing was 0.05m, the culture pond system could obtain the best hydrodynamic conditions, the overall flow velocity of the culture pond was higher, the centripetal trend of the dirt movement was more obvious, and the flow field motion state was most conducive to the discharge of dirt in the culture pond. The results of this study can provide a theoretical basis for the layout of the inlet pipe of the square arc-angle culture pond.