It is of great practical significance to establish the evaluation system of power equipment utilization efficiency aiming at power grid capacity optimization for collaboration of power grid planning and construction. An evaluation system of power equipment utilization efficiency aiming at power grid capacity optimization is introduced. Four major evaluation indices, including capacity-load ratio, maximum load rate, annual equivalent mean load rate and annual mean utilization time, and power grid capacity optimization limits are given. Considering the key factors influencing utilization efficiency, and a capacity optimization method is adopted to enhance the overall utilization efficiency. Case study in Yunnan power grid verifies the reasonability and effectiveness of the evaluation system and the optimization method proposed in this paper.