In the production process of TFT-LCD substrate glass，in order to eliminate the sharp edges and reduce edge stress，it is necessary to grind the four edges of the glass.Because the grinding process generates a lot of heat instantaneously，a large amount of water cooling is used to overcome quality defects such as edge burning and broken.In order to ensure cooling effectiveness and avoid pollution on the glass surface ，it is required to use the expansive pure water with 10 megohms for grinding cooling.The wastewater recycling and reuse system was developed to reduce pure water consumption and renovation experiments were conducted on the G5 generation production site.By comparing the water quality and glass processing quality before and after the renovation，it was shown that the amount of pure water used had been significantly reduced，the recycling water had no negative impact on the surface pollution of glass，and edge defects can also meet quality control requirements.After the renovation，the production cost has been greatly reduced，which has important practical application value.