Abstract: Studies were made on the process of on-site color penetration testing of nuclear power plants as from the aspects of penetrant pollution control, convenience of test block operation, canned penetrant release, waste tank disposal and test block reliability verification was taken, and solutions for the process optimization of the field dye penetrant testing in the nuclear industry were proposed, including the design and production of auxiliary fixture and verification methods of test block reliability, etc., which may provide references for peers.