The utility model relates to a process device for producing dipropylene glycol in a dimethyl carbonate device. According to the technical scheme, the process device comprises a feeding mixer, a mixing tank, a heater, a reactor, a buffering tank, a dehydrogenation tower, a DPG (Dipropylene Glycol) product tower and a TPG (Triphenyl Guanidine) product tower, wherein propylene glycol, epoxypropane and sodium methoxide are conveyed into the feeding mixer by a delivery pump; the feeding mixer is connected with the mixing tank by a pipeline; the output end of the mixing tank is connected to the heater; heated raw materials enter the reactor; an outlet in the upper end of the reactor is connected to the upper end of the buffering tank and the lower end of the buffering tank is connected to the dehydrogenation tower; the bottom output end of the dehydrogenation tower is connected to the DPG product tower; the bottom output end of the DPG product tower is connected to the TPG product tower. The process device for producing the dipropylene glycol in the dimethyl carbonate device has the beneficial effects that the problem that the quality of a product in dipropylene glycol industrial production is poor is solved successfully; all the refined and purified dipropylene glycol products reach the LO+ grade so that the benefits of the device are improved greatly. Meanwhile, a continuous production process is adopted so that the defects that the operation is complicated, the reaction is slow and the energy consumption is high are solved.