Under conditions of limited maintenance resources,how to select equipment is the basis to make maintenance plan and maximize the effect of maintenance. Based on transmission and transformation equipment risk assessment guide rule, this paper proposes a maintenance prioritization method of transmission and transformation equipment based on maintenance risk return. The process of risk assessment for equipment, a failure probability model which is suitable for risk assessment, a model for the multilevel effects of different failures to equipment itself, human, environment, system, society and the selection method of maintenance prioritization decision value are introduced. Taking RBTS system as an example, the case study quantitatively shows equipment’s failure probability, failure consequences and the calculation process of maintenance prioritization decision value. Different applications of the method under different application conditions are also demonstrated. Compared to the traditional methods of selecting maintenance equipment, this method has a more effective failure probability model, a more comprehensive evaluation system of consequence severity and a wider range of applications.