The utility model specifically provides a combined power generation device of a power transmission tower, solving problems that an existing power generation device is low in power generation efficiency and high in power. The device comprises a power supply, a switch, a stepping motor, a solar cell panel connected with the output shaft of the stepping motor, an ULN2003 stepping motor driver chip, an MSP430 single-chip microcomputer, a light sensor, and a wind power generation device. The output end of the solar cell panel is connected with the cathode of the power supply. The anode of the power supply is connected with the input end of the MSP430 single-chip microcomputer and a contact of a relay. The power supply is connected with the light sensor and the wind power generation device. The output end of the MSP430 single-chip microcomputer is connected with the input end of the stepping motor driver chip and the coil of the relay. The other contact of the relay is connected with the input end of the stepping motor driver chip. The output end of the stepping motor driver chip is connected with the stepping motor. The combined power generation device improves solar power generation efficiency, and provides sufficient electric energy for electric devices of a power transmission tower.