Abstract: The bushing is a critical component of pole-mounted vacuum circuit breakers. Improving its local electric field distribution helps reduce the partial discharge of the circuit breaker. Embedding a shielding mesh in the bushing is an effective method to optimize the electric field distribution. This paper simulates and analyzes the electric field distribution of the bushing with shielding meshes of different dimensions. The results indicate that the optimal length of the shielding mesh is 80 mm to 110 mm, and the optimal diameter is 50 mm to 58 mm. Based on these optimized dimensions, further structural design improvements are made to the shielding mesh.