The invention discloses a simulation method for a heat exchange process of a carrier rocket low-temperature storage tank. The simulation method includes dividing a solid wall of the storage tank into three layers of thermal capacity units along axial and radial directions respectively, creating a heat-conducting and heat-convecting mathematical model, and creating a system simulation model considering change of heat conductivity of storage tank materials with temperature in a low-temperature environment, heat convection between pressurized gases and the solid wall of the storage tank and influences of solid-wall heat capacity and heat conduction to pneumatic-cushion pressure temperatures. The simulation method has the advantages that simulation accuracy of pneumatic-cushion pressure and temperature change during simulating pressurizing and heat exchanging of the low-temperature storage tank is improved.