The invention provides a real-time global illumination method for a sub-surface scattering object on the basis of the radiosity, which is mainly divided into three steps of: 1) pre-calculating: pre-calculating an energy transmission matrix of a scene by the traditional approximate dipole model and the radiosity, and storing in a sparse matrix mode; 2) calculating an energy transmission process by a quick sparse matrix library of a GPU (Graphics Processing Unit), and obtaining energy acquired by each surface patch; and 3) obtaining the final global illumination effect by a quick photon collection algorithm. On the basis of the certain pre-calculation basis, the real-time global illumination effect for the sub-surface scattering object can be obtained.