Abstract: Based on actual working conditions of engineering application of suspended TIG automatic welding process, X-ray non-destructive testing and metallographic observation technology were used to analyze quality of surface formation of weld, internal weld and welding leakage. For both milled and unmilled welding leaks, mechanical properties at room temperature and low temperature, as well as fracture morphology, were analyzed by mechanical test and scanning electron microscopy testing technique. Based on experimental research, validation work was carried out on procedural application of unsupported suspended TIG. The results showed that formation of suspended TIG welding leakage was full, and there were no welding defects inside of weld and welding leakage. Mechanical properties of welded joints with welding leakage were higher than those without welding leakage, and presence of welding leakage enhanced mechanical properties of weld. Under room temperature testing conditions, fracture location of welded joints with unmilled welding leaks located at base metal zone near weld, while fracture location of welded joints with milled weld leakage located at fusion line. Under low temperature testing conditions, fracture position of welded joints in two states located at fusion line, and fracture morphology of all welds exhibited ductile fracture characteristics. The performance test results of unsupported suspended TIG engineering samples were consistent with experimental research results, and preliminary progress has been made in engineering application.