In view of the problems of many welds, high welding difficulty and easy to produce defects in the welding of hydraulic cylinder parts,the test is carried out by MAG welding with common material for hydraulic cylinder. In order to ensure the welding quality and prevent the welding cracks and other defects,the welding parameters are made for different materials,and appropriate technological measures are provided.When evaluating the postwelding test piece,it shows that the weld is well formed,the welding deformation is small,the surface and internal defects are few,and the ultrasonic flaw detection and mechanical property detection are qualified. The results show that the welding quality is good,the welding procedure is reasonable and feasible,and it can completely meet the working requirements of the hydraulic cylinder of construction machinery.