The article mainly focuses on stainless steel. It first elaborates on the characteristics of stainless steel, including different types like austenitic, martensitic, ferritic and duplex stainless steel, and its properties such as corrosion resistance. Then it presents main welding methods like resistance welding, manual arc welding, gas-shielded welding, laser welding and others, along with their application scopes and operating points. It also analyzes technical difficulties in welding such as hot cracking, intergranular corrosion, welding deformation and porosity, and proposes corresponding solutions. Overall, it emphasizes the complexity and importance of stainless steel welding.