The article presents the results of numeric simulation of operating process in rocket engine of new type on cryogenic solid propellant (CSP) which contains both oxidizer and fuel at temperature lower than its melting temperature. Mathematical at model of operating process is based on non-stationary axisymmetric Navier - Stokes complete equation system for gas (including k-e turbulence model) and heat and mass transfer equations for CSP. Calculations are made for CSP oxygen + hydrogen and oxygen + methane. Disk-stack and sponge arrangements of CSP structure for channel propellant grain are considered and influence of propellant structure dimensions on operating process is analyzed. , The article conclusdes that stable combustion of CSP oxygen + hydrogen is impossible under given condition, but CSP oxygen + methane allows to ensure stable operating process in combustion chamber and to control regression rate of the GSP components by specifying the propellant internal structure. Additionally, the article presents main features of operating process in a novel kind of hybrid rocket engine on cryogenic propellant, where component in liquid phase state and the other component are solid.