A human body back-scattering inspection method and system are discloses. The method includes: obtaining a back-scattering scan image of a human body under inspection; distinguishing a body image from a background image in the back-scattering scan image; and calculating a feature parameter of the background image to determine whether radioactive substance is carried with the human body. With some embodiments of the present disclosure, it is possible to determine whether any radioactive substance is carried with a human body during back-scattering inspection of the human body. In further embodiments of the present disclosure, it is possible to approximately determine which part(s) of the human body carries the radioactive substance. This improves efficiency of inspection.