This standard details the hot helium leak detection test method for high temperature and pressure components of nuclear fusion reactors under high temperature and high voltage helium environment. It is applicable to the sealing test of internal components of nuclear fusion reactors, vacuum chambers, sealing structures and components under Miscellaneous high temperature environment, as well as the sealing test of Miscellaneous high temperature or high voltage components. A number of relevant standards are cited, including the manufacture, inspection and acceptance of Pressure Vessel (GB/T 150.4-2011), the terminology in nondestructive testing (GB/T 1 2604.7 - 2021), etc., to ensure the standardization and Reliability of the test. No additional terminology is required, and the terms and definitions defined in the relevant standards are applicable. Samples are tested in a high temperature and high voltage helium environment, and suitable leakage detection methods are used to ensure that the sealing performance of the components meets the requirements, which can effectively deal with the environmental requirements of nuclear fusion reactors.