The article deals with different methods of parallelization of an algorithm of solving 2D unsteady problems of radiation gas dynamics in eulerian variables. The diffusion approximation is employed to describe the radiation field. Parallel methods of the solution of these problems are developed on the basis of multiprocessor transputer based systems with distributed memory. These methods combine different manners of parallelization: in accordance with radiation frequencies groups, geometrical parallelization using “Domain Decomposition” method) and functional parallelization.