The invention relates to an electric spacer cart for maintenance operations of a 4-bundle conductor of a 500kV power transmission line. The spacer cart comprises a suspended driving mechanism and a manned operating and control mechanism. The suspended driving mechanism comprises an upper cart support, and two symmetrical main driving wheels on the left and the right are arranged on the upper cart support. The manned operating and control mechanism comprises a lower cart support for maintenance operators to sit on. The lower cart support is connected to the upper cart support from underneath. A power supply, a DC motor, a transmission shaft and an operating handle are arranged in the lower cart support. A transmission gear is arranged on the transmission shaft which is connected with the main drive wheels through chains. The power supply is connected with the DC motor which is connected with the transmission gear. The operating handle is connected with the DC motor and the transmission gear. The spacer cart is simple in structure, convenient for suspension, safe in usage, and suitable for 500kV large-span power transmission lines with 4-bundle conductors. The spacer cart reduces the labor intensity of the operators, saves time and labor, and largely improves the work efficiency of power transmission line maintenance operations.