Abstract: This paper introduces the technical characteristics of high-temperature magnetic particle testing of the main steam and main water supply pipe-related welding joints of HPR 1000 pressurized water reactor nuclear power plant, describes the characteristics of high-temperature magnetic powder, designs and manufactures the simulated sample blocks and specimens for procedure qualification, and carries out sensitivity verification of high-temperature magnetic particle testing. It also introduces the implementation process and safety measures of high-temperature magnetic particle testing.It can provide a reference for peers who tend to implement magnetic particle testing under high temperature conditions.