The invention belongs to the technical field of coal chemical industry and petrochemical industry equipment, and particularly relates to a process method for a pressure reduction system. The process method comprises the following steps that 1, basic composition of the pressure reduction system is determined, specifically, the pressure reduction system is used for high-temperature and high-pressureworking conditions and comprises a main process module, a mechanical control system, a thermodynamical balance system and an intelligent control system; 2, the work procedure of the pressure reduction system is determined, specifically, a process medium enters the main process module, under an instruction of the intelligent control system, the mechanical control system outputs torque, all valvesof the main process module are opened and closed and subjected to opening degree adjusting, thus pressure reduction of the process medium is achieved, and then the process medium flows out from the pressure reduction system; and 3, a specific process of the pressure reduction system under different working states is determined. According to the process method for the pressure reduction system, theautomation degree is high, an integral prying device can achieve unmanned-interference operation, and the operating and maintenance costs can be lowered greatly.