Fossil resources are increasingly exhausted and energy problems are facing severe challenges. The synthesis of ethanol from abundant lignocellulose is conducive to alleviating energy shortage, reducing environmental pollution, and achieving sustainable development. In this paper, compared with the traditional process, the whole process simulation of lignocellulose to biofuel ethanol is established, and a deep-eutectic solvents (DES) pretreatment process for Lignocellulose is proposed. Firstly, to verify the feasibility of the process, the steady-state simulation of the biofuel ethanol production process is carried out using Aspen Plus. Secondly, based on the steady-state simulation, the process is optimised to obtain the optimal operating parameters. Finally, DES is used as an entrainer to increase the concentration of ethanol, and its mechanism is investigated by molecular dynamics simulation (MD). The simulation results show that the DES has good effect in pretreatment and extractive distillation. The final yield of ethanol is 16.8 kg/h and the purity is 99 %. The results of molecular dynamics simulation show that the interaction between DES and water is much larger than that between DES and ethanol. The results are consistent with the process simulation results.