Abstract: Particular strictness on sphere constraction has made it significant to achieve the success of sphere assembling at ouce in hydraulic and airtight tests. Here is a summary of sphere quality control made by the author based on learning the advanced experiences from others and his own practice in this field. Explained in detail are the criteria of quality control, request and the measurez that should be taken in the way of its assembling, welding and test. And accentuated in particular is that quality control and test must be carried out very conscientiously at cach process of operation in order to guarantee the quality of a sphere as a whole.