Abstract: As the first research institution of China on radiation protection with a history of more than 60 years, Department of Radiation Safety of China Institute of Atomic Energy (formerly Technical Safety Office) has carried out continuous exploration and research in the fields of radiation protection standards, radiation protection monitoring, radiation environment monitoring and evaluation, natural radiation exposure and national dose estimation, energy and environment, nuclear and radiation emergency response and management, radioactive waste safety management and minimization, and has made a number of scientific and technological achievements. The achievements mainly include: 1) presiding over or participating in the documentation and research of previous radiation protection standards of China; 2) research on individuals, workplaces, environment and effluents monitoring technology, establishing systematic monitoring and evaluation methods, developing radiation protection monitoring instruments; 3) undertaking the radiation protection guarantee and technical support for military scientific research and production, radiation protection during the overhaul of 101 heavy water reactor, and radiation environment quality assessment of nuclear industry for the past 30 years; 4) carrying out the research on the key issues of radon exposure and other natural radiation exposure issues and estimation of national radiation dose in China; 5) carrying out comparative study on environmental impact of different energy chains; 6) operating the national nuclear emergency monitoring technical support center and participating in all previous national nuclear and radiation emergencies; 7) research and practice of radioactive waste minimization.