The sewage treatment of the natural gas purification plant uses biochemical and electrodialysis with evaporative crystallization sewage treatment process for the first time, and achieves the goal of zero sewage discharge for the first time by relying on the methods including sewage classification during collection, separate treatment for different quality sewage group and recovery of segregated grades of water. As the above process is used for the first time, there are operating issues such as serious scaling of electrodialysis equipment, poor evaporative crystallization effect, return water quality and water volume affecting the operation of circulating water system in the process. By means of optimizing the operating parameters of electrodialysis and evaporative crystallization units, adopting measures such as pre-filming and adding sulfuric acid to reduce pH to slow down the corrosion of circulating water system, and technical transformation to upgrade the water quality; the successful application of zero-discharge sewage treatment technology in natural gas purification plant is guaranteed. The above experience provides reference for the successful application of zero-discharge sewage treatment technology in similar natural gas purification plant.