Surface radiative exchange is widely used in the fields related to industrial and environment. Accurate and rapid calculation of the surface radiant heat flux can predict and prevent accidents. In this study, a solver for surface radiative exchange based on the OpenFOAM platform is developed. The solver’s accuracy can be verified by calculating the net heat rate of the cubic cavity and the triangular-prism geometries. The solarLoad radiation model is used to study the variation of heat flux with respect to the solar incidence angle for a satellite in orbit and a human standing in a room with a window. Finally, a Graphical User Interface (GUI) based on the PyQt5 for this solver is developed to simplify the operation process and make the solver user-friendly.