Abstract: The reactor pressure vessel (RPV) is an irreplaceable key equipment in nuclear reactor. It was found that 2# weld defects of RPV exceeded the standard in the Tianwan Nuclear Power Plant inspection stage. The 2# weld was located in the core barrel, which was strong radiation area. To evaluate the acceptability of defects, the pressurized thermal shock analysis was done for 2# weld of RPV using the finite element method, which included small break loss of coolant accident and PRZ-SV inadvertent opening. The calculation results show that the result of finite element analysis is coincided basically with results using foreign expert recommended method. The 2# weld of RPV, in which the brittle transition temperature of the final life is lower than that of the minimum allowable, can be satisfied with the requirement of resistance to brittle fracture.