Abstract: This paper introduces the design parameters of the passive residual heat removal heat exchanger for American advanced passive pressurized water reactor（AP1000）,describes the fabrication process for the head,tubesheet,heat exchange tube,corrugated plate and support frame assembly of the heat exchanger,mainly in terms of material,forging,welding,and heat treatment,and also analyzes the crucial steps for the support frame assembling,tubesheet plate welding,tube penetration welding of C tube bundle,closure/head welding,heat treatment,hydraulic（pressure） test,and etc.in the process of heat exchanger assembling.