The invention provides a system and process for co-production of dimethyl carbonate and ethylene glycol. The system comprises an ethylene carbonate preparation unit and an ethylene carbonate alcoholysis unit which are connected with each other, wherein the ethylene carbonate preparation unit comprises a fixed bed reactor and a low boiling fraction removal tank which are connected; and the fixed bed reactor is filled with a supported ionic liquid catalyst. The process comprises the following steps of adopting carbon dioxide and ethylene oxide as raw materials, reacting in the fixed bed reactor to generate ethylene carbonate; and mixing with an alcoholysis reaction catalyst after purification, and reacting with methanol in a reactive distillation column and generating the dimethyl carbonate and the ethylene glycol. According to the process, the conversion rate of ethylene oxide is improved, the procedure of separating a traditional homogeneous catalyst from ethylene carbonate is avoided, so that the energy consumption of the process is reduced and the technological process is simplified.