In view of the maintenance management of electric transmission equipment， a new maintenance technology based on risk assessment is proposed. Through the procedure of risk assessment and the method of decision-making， the basic technical framework that applies risk-based maintenance（RBM） to the maintenance of electric transmission equipment is developed. By employing the risk assessment theory and interval analysis， the technology has not only made maintenance decision-making much more economical but also greatly enhanced technology operability. Application of the technology in an actual regional power grid shows that it can comprehensively evaluate the risk to equipment and make expeditious decision-making， signaling good application prospects for the technology proposed.