Abstract: The nuclear safety class valves are very important in nuclear power plants, and the focused concern of National Nuclear Safety Administration. According to requirements of relative nuclear safety regulations, mock-ups must be made by applicants, at the same time, all corresponding qualification tests must be carried on. But no detailed requirements were given on how to choose the mock-up size and what qualification tests should be carried on. Combined with safety review practices, some basic requirements on how to choose the mock-up size, how to do the preparation work, how to control the process of manufacture and some mistakes may be made in qualification test are presented in this paper for applicants and nuclear safety technical reviewer to refer.