Aiming at the characteristics of dynamic positioning vessel with a large number of propellers, the research on the interference between propellers of dynamic positioning vessel is carried out. Based on the RANS equation and RNG k-εturbulence model, a numerical method for rotating flow is presented by using a sliding mesh. Firstly, the open water characteristic of propeller is calculated, and then the thrust reduction under different spacing, azimuth and advance speed is studied successively by using the method of control variables. The validity of the calculation is verified by comparing with the experimental results of predecessors. Relevant computational research provides a basis for thrust allocation algorithm and has good engineering application value.