The invention relates to a radiation protective control method for repairing a damaged spent fuel assembly of a mega-kilowatt nuclear power plant. The radiation control method comprises the following steps of A1, carrying out sipping test and ultrasonic or eddy current inspection on the damaged spent fuel assembly; A2, analyzing a radiative source term according to the test result and the inspection result; A3, developing a radiation protective optimized action form and a control point document according to the analysis result of the radiative source term, and finishing the work of a radiation protective control document; A4, performing the radiation protective control in the repairing process of the damaged spent fuel assembly on the basis of the radiation protective control document. According to the radiation protective control method disclosed by the invention, standardized operation can be realized by combining practical experience and adopting scientific and reasonable radiation protective means, so that accidental release of radioactive substances in the repairing process of the damaged spent fuel assembly is prevented, and radiation risk for operators is reduced.