Abstract: The numerical simulation is one of the important methods of studying physical process. In this paper, a 3D discrete view factor method is proposed for the equivalent model of two-region uniformly in inertial confinement fusion (ICF). The blocked elements are culled by quadtree data structure when the inner wall of a hohlraum is self-occlusion in irradiation process. The parallelism is analyzed on discrete view factor and then the parallel computation of fluence distribution on target is realized on GPU. The algorithm has been realized in simulation software IRAD3D1.0, and the correctness is verified by comparing with analytical solution. Different simulation results show that the software is versatile and efficient. Finally, the practical application on influencing factors of symmetry distribution is given.