The invention relates to the technical field of electric control cabinet machining equipment and provides an electric control cabinet L-shaped steel member punching device, so that the problems that when a traditional L-shaped steel member is punched, machining personnel need to measure first to determine the hole positions, then the determined positions are punched one by one, the punching efficiency is low, and the precision is low are solved. The device comprises a machining table and a rack arranged at the upper end of the machining table. A hydraulic pressure station is mounted at the upper end of the rack, and the output end of the hydraulic pressure station is connected with two hydraulic rods through liquid conveying tubes in a penetrating mode. The hydraulic rods are fixedly mounted on the inner top wall of the rack, and a same lifting plate is mounted at the output ends of the two hydraulic rods. A plurality of parallel punching heads are detachably mounted at the lower end of the lifting plate through fixing seats correspondingly. An adjustable supporting device is arranged under the multiple punching heads. The electric control cabinet L-shaped steel member punching device is particularly suitable for electric control cabinet interior L-shaped stele member efficient and precise punching, the social application value is high, and the application prospects are good.