Abstract: RV (Rotor Vector) reducer is an important transmission device in the industrial robot system. It is usually composed by an involute planetary gear and a cycloidal pin wheel. In this paper, a novel analysis method of pins was proposed based on theoretical force analysis with the consideration of real wearing condition. By simulating the pins with the improved analysis method, shear force and bending stress on the pins can be calculated. To reduce the effect caused by shear force and bending stress, the short pins were used to replace traditional long pins. Experimental results show that, the usage of short pins not only can eliminate shear force and bending stress, but also decreases the occurrence of slippage during meshing, and that makes the RV reducer with higher reliability and longer service life.