An improved particle swarm optimization (PSO) algorithm is presented to optimize the texture shape of the sealing ring in order to enhance the load carrying capacity (LCC). The shape optimization uses the unrelated generation method of the texture curves, and two splines are applied to fit the boundary of the texture to improve the continuity. The inertia factor is adjusted through the differential strategy to enhance the local optimization capacity. The optimization model is verified by two optimization cases. The optimized texture is bullet-shaped. The increase of inlet oil pressure transforms the optimized texture from the bullet shape to the inner spiral shape. In addition, the increase of the texture depth leads to the gradual elongation of the texture shape. The increase in the number of textures flattens the seal texture. The results shows that the improved PSO algorithm has high global optimization ability of the texture shape for the sealing ring in the vehicle transmission through appropriate parameter settings.