Abstract: The required chemical content range of Primary Coolant Piping （Static cast elbow, centrifugally cast pipe） by Design and Construction Rules for Mechanical Components of PWR Nuclear Islands （RCCM） （French Norm） is wide. The result of manufacturing qualification test, which was performed by YANTAI TAIHAI MANOIR NUCLEAR EQUIPMENT CO. LTD. （THM）, shows that qualification pieces satisfied the chemical requirement of RCCM may not satisfy its mechanical requirement. CNPEC/ECE together with THM analyzed the anticorrosion and strengthening mechanism of Material Z3CN2009M （French Brand） for Cast piece of 1000 MW PWR （CRP1000） Primary Coolant Piping through metallography methods. Strictly internal chemical control range of ladle analysis was established and it makes the mechanical property of cast piece of CPR1000 PWR Primary coolant piping satisfy the RCCM requirement without losing the anti-corrosion property and weld ability. The mechanical test value obtained has rich margin, little degree of separation and exhibits stable quality and advanced overall properties. This success solved the preliminary requirement for domestic making of Primary Coolant Piping of NINGDE and YANGJIANG Nuclear Power Plant and finally realized the domestic manufacturing of Primary Coolant Piping cast piece for CRP1000 Nuclear Power Plant.