Using Na-bentonite from Xinjiang as materials of geosynthetic clay liner (GCL), the authors performed the dry purification middle test and industrial test to determine the best production condition. The results prove that, under the best condition, the performance of the product is greatly improved, and the expansion index and the methylene blue adsorbed by bentonite can reach the GCL product standard without the addition of any subsidiary materials. The outcome obtained by the authors can be used to directly guide industrial production and hence have a very important practical and economic significance.