In order to study the aerodynamic influence of pitch angle on the contra rotation propeller (CRP) and improve its aerodynamic performance, at the inlet Mach number of 0.453, by adjusting the pitch angle of the aft propeller, a 6×6 contra rotation propeller was numerically calculated, and the variation law of pitch angle on aerodynamic interference between the contra rotation propeller was studied. The Unsteady Reynolds-Averaged Navier-Stokes (URANS) equation combined with the SST turbulence model is used in the calculation, and the T-Rex high quality mesh generation technique is used. The calculation results show that there is complex aerodynamic interference between the front and aft propellers of contra rotating propeller, the aft propellers can absorb a part of the tangential slip flow energy of the front propellers, and the aerodynamic efficiency is higher than that of the front propellers. The aerodynamic parameters of the front and aft propellers fluctuate 12 times in a rotating cycle. When the pitch angle of the front propellers is 54° or 56°, the efficiency of the front propellers is slightly improved when the pitch angle of the aft propellers is reduced, while the pull coefficient and power coefficient of the aft propellers are significantly increased, and the efficiency of aft propellers increased by 4% and 6.4%. The Ct 、 Cp and n fluctuation amplitude of the aft propeller increases. In addition, in order to offset the torque of the front and aft propellers and improve the overall aerodynamic performance of the contra rotation propeller, the pitch angle of the aft propellers should be appropriately reduced under this working condition.