Abstract: Combined with welding defects in austenitic stainless steel welding practice,the samples were tested and analyzed theoretically.Causes to welding defects were concluded corresponding measures to eliminate welding defects were proposed in order to avoid such defects fundamentally. The defects mentioned had a common feature that the defects were not caused by welding materials or welding parameters,but caused by some inappropriate microelements in the base metal of austenitic stainless steel. The fundamental measures to eliminate the welding defects were to control and optimize microelements in the base metal,while it was difficult to eliminate the welding defects by welding technology,especially in the case of self-melting welding of stainless steel sheet. In order to improve weldability of stainless steel in essence,weldability and workability should be fully considered in the process of material composition design and production quality control.