Abstract: There were several problems after the application of methanol-containing waste water regeneration system in Yanchang gas field, including significant fouling or corrosion, unstable operation, unqualified product, especially the failing of methanol product to meet the design requirements. Both NRTL equation as rational thermodynamic model and Aspen plus software were used to simulate the whole methanol regeneration process, which proved that this software could successfully simulate and optimize methanol regeneration system. An optimizing process simulation of methanol regeneration system was established by adding the cooler and pump, changing plate form, increasing the plate height. Results showed that the concentration of methanol and reinjection water both met the design requirements. Industrial methanol regeneration unit after renovation based on optimizations ran safely and smoothly, with the concentration of methanol and reinjection water were 96.10% and 0.19%, respectively. Both parameters were close to optimized results, indicating that the optimization simulation project was feasible and accurate.