The invention discloses a dimethyl ether production system with a waste heat electricity generating function and a production process. The system comprises a comprehensive methyl alcohol pre-heater; the top of the comprehensive methyl alcohol pre-heater is connected with the upper part of a methyl alcohol gasifying tower; the top of the methyl alcohol gasifying tower is connected with the lower part of a heat exchanger; the upper part of the heat exchanger is connected with the top of a reactor; the bottom of the reactor is connected with the bottom of the heat exchanger; the top of the heat exchanger is connected with the upper part of the comprehensive methyl alcohol pre-heater; the upper part of the comprehensive methyl alcohol pre-heater is connected with the lower part of a dimethyl ether rectifying column; the bottom of the dimethyl ether rectifying column is connected with the upper part of a methyl alcohol recycling tower; the methyl alcohol recycling tower is connected with the comprehensive methyl alcohol pre-heater; the bottom of the methyl alcohol recycling tower is connected with the comprehensive methyl alcohol pre-heater; a methyl alcohol recycling tower reboiler is arranged at the lower part of the methyl alcohol recycling tower; the upper part of the reactor is connected with a steam drum; the steam drum is connected with a backpressure engine; the backpressure engine is connected with the methyl alcohol recycling tower reboiler. By adopting the production process of the system, gradient energy utilizing and waste heat electricity generating can be realized, and the energy consumption is low.