The stainless steel diaphragm pump is improved on the basis of the QBY pneumatic diaphragm pump. It has an added built-in air distribution valve, simpler structure, larger flow, higher head, more stable performance, and integrates the advantages of self-priming pump, submersible pump, shielded pump, slurry pump, impurity pump, etc. It is widely used in chemical, petroleum, pharmaceutical, mining, papermaking, cement plant, steel plant, power plant, coal processing and other industries.