Abstract: Based on the theory of multi-field coupling of porous media and the mass transfer of chemical reaction, the flow velocity, pressure and product concentration between copper oxide particles of ammonia in the process of ammonia leaching were studied by using Comsol Multiphysics simulation software. The model discussed in this paper set the inlet from the left, middle and right parts of the center of the tank, and the outlet from the right side and the middle of the bottom of the tank. The effects of different inlet and outlet positions of ammonia leaching tanks on the concentration of copper-ammonia complex during ammonia leaching were investigated. The corresponding copper ammonia complex concentration and the kinetics process of the flow velocity and pressure distribution of the liquid in the ammonia leaching tank were obtained. The results showed that the formation concentration of copper-ammonia complex could be obviously affected by changing the position of the inlet and outlet of ammonia leaching tank. The ammonia entering from the middle of the ammonia leaching tank and flowing out from the bottom right corner had a high velocity and the effect of ammonia leaching was good. Meanwhile, the copper oxide particles had a full reaction with ammonia, and the concentration of copper ammonia complex was the highest. The research results had important guiding significance for the equipment design of ammonia leaching complexation.