The utility model provides a transformer substation prevents that mistake cat ladder blocks, relate to transformer substation's climbing equipment, which comprises a vertical ro, telescopic machanismand foot bar, the pole setting is vertical installs in the equipment outside, telescopic machanism is located the lower extreme of cat ladder, telescopic machanism sliding connection is in the pole setting, telescopic machanism is connected to form by a plurality of extension means, extension means includes wire rope, the hoist pole, slider no. 1, slider no. 2, bracing piece and connecting rod, the bracing piece, the stable triangle -shaped structure that connecting rod and pole setting formed, ensure when bearing pressure firm indeformablely. Electrification module's cat ladder blocks telescopic machanism and is the contraction state, receives the eminence with the foot bar of cat ladder lower part, ensures the maintainer and can not climb by mistake, the cat ladder of outage module blocks the drop -down extension state that is of telescopic machanism, makes the equidistant equipartition of foot bar of cat ladder lower part, and the easy access personnel climb up the overhaul of the equipments. This is novel ensures the maintainer and distinguishes outage module and electrification module, prevents the mistake cat ladder, the normal operating of guarantee personal safety and electrification module equipment.