Abstract: By comprehensive analysis of Guide 103/07 of Nuclear Safety of the People’s Republic of China（HAD 103/07）,In-Service Inspection Rules for the Mechanical Components of PWR Nuclear Islands（RSE-M）,Section XI of American Society of Mechanical Engineers Boiler and Pressure Vessel Code（ASME）and French 1999 decree about in-service supervision items for main primary and second loops of PWR Nuclear Plant,and etc,as well as combined with the present domestic engineering practice in pre-service inspection,besides the analysis of the affects respectively caused by that pre-service inspection executes before hydrostatic test and hydrostatic test executes before pre-service inspection,technique views were formed for operation occasion between pre-service inspection and hydrostatic test for main primary system.