The H-beam automatic assembly machine is mainly composed of a mast assembly, a tie rod system assembly, a hydraulic system assembly, an input and output raceway assembly, and an electronic control system. The main parts of this machine are all welded structural parts, which have high strength and light weight. And important parts have been treated to eliminate stress and are not easily deformed. The main transmission part adopts the transmission mode of the motor-Changzhou cycloidal pinwheel reducer-the driving roller (the front and rear conveyor rollers pass through the sprocket chain pair transition). Its linear speed, that is, the assembly speed, adopts AC frequency conversion speed regulation. Optional within the range of 0.5-6 M/min. The main drive roller and the main pressure roller are made of special steel and have been specially processed, with good wear resistance and high precision. The positioning and centering action of this machine is driven by the hydraulic system. First, it is initially positioned and centered by the tie rod system, and then is accurately centered and clamped by the gantry assembly. The clamping process in the precise determination of the wing plate is realized by the hydraulic system-rack and pinion pair-sprocket chain pair-gear pair-screw pair transmission. The clamping process in the precise determination of the web is realized by the hydraulic system-rack and pinion pair-sprocket chain pair-screw pair transmission. The main pressure roller lifting is also realized by hydraulic pressure, and the whole process is all controlled by electronic buttons. Centralized operation, easy, convenient and accurate positioning. The positioning and centering speed, the size of the pressing force, etc., can be adjusted at will on the H-section steel production line according to the requirements of the section steel specifications and operating proficiency. The special structure of hydraulic drive and mechanical synchronous positioning and centering can ensure accurate positioning of the web for any width of the wing. The hydraulic lifting positioning device at the front of the mast is used to align the wings and webs to ensure the straightness of the end face of the H-shaped steel. The speed of H-beam assembly can be changed by changing the output frequency of Taiwan's Taian inverter.