Abstract: Based on an in-depth study of the weldability of LG900QT high-strength steel specifically for engineering machinery, basic welding guidelines for this steel have been established. During the formulation process, the special structural characteristics of the equipment, risk factors affecting weld quality, and the importance of adhering to relevant standards were fully considered. Consequently, the welding methods, welding materials, process parameters, and post-weld treatment control measures for LG900QT high-strength steel were clearly defined. Additionally, two sets of process evaluation test schemes were designed based on the essential and auxiliary elements of the relevant welding process evaluation standards. The test samples were strictly prepared according to the welding process evaluation standards, undergoing processes such as bevel preparation, assembly welding, post-weld treatment, and non-destructive testing of the weld. Subsequently, full-thickness joint tensile specimens, weld and heat-affected zone impact specimens, full-section metallographic specimens, and hardness specimens were cut and subjected to a series of tests. The results of non-destructive testing and destructive testing indicate that the use of the defined welding methods, welding materials, welding parameters, and post-weld treatment standards results in excellent welding performance for LG900QT high-strength steel, providing reliable support for effective welding of product equipment.