Taking ZX50CA drilling-milling machine as the research object, the hydraulic technology was used to modify the pressing system, a friction stir welding equipment was designed for magnesium alloy sheet. An AZ31 magnesium alloy sheet with 3 mm thickness was used for the welding experiment. The results show that when the rotating speed is 1 400 r/min, the welding speed is 15 mm/min, and the pressure is 1 500 N, the welding joint surface forms well. The experiment proves that the equipment can satisfy the requirement of the friction stir welding process parameters, suitable for friction stir welding experiment research; relative to the large-scale specialized friction stir welding equipment, it is low cost, flexible, convenient. It provides reference for development of friction stir welding equipment for magnesium alloy sheet.