The invention relates to an intelligent substation secondary equipment operation and maintenance object safety error prevention method and device, belonging to the comprehensive automatic technology field of intelligent substation in an electric power system. The method and apparatus of the invention firstly edits and generates a secondary operation and maintenance sequence ticket for the secondary equipment operation and maintenance object in need of operation and associates each operation step of the generated secondary operation and maintenance sequence ticket with relevant blocking logic. Then, the operation and maintenance state of the secondary equipment is online monitored based on relevant signal and state vector as well as on the each operation step of the generated secondary operation and maintenance sequence ticket for the secondary equipment. Finally, the error prevention blocking real time calibration is performed based on the associated error prevention blocking condition of the secondary equipment operation and maintenance object and the real time state of the associated equipment as well as through calculations under the logic conditions. For the above steps, it is possible to realize safety error prevention of secondary equipment operation and maintenance object, and the overall operation and maintenance process can be completed in a direct, visible and closed loop.