Abstract: An occupational exposure occurs during the performance of job duties and may place a worker at risk of infection in terms of health or life.In this review the basic concept of occupational exposure and the characteristics of occupational exposure in nuclear medicine practice were introduced at first.And then introduced the global rapid trends in diagnostic and therapeutic nuclear medicine modalities applied in medical procedure.The external radiation protection in nuclear medicine practice mainly including time, distance and shielding were emphasized.Moreover, a literature retrospective review was undertaken focusing the hot topics in radiation protection fields, like pregnancy, fetal, PET-CT and radiation low-dose biological effects.