This article takes the water quality characteristics of mine water in the border area between Inner Mongolia and Shaanxi, the existing problems in the original treatment process, and the modification of the salt separation equipment as the starting point. It provides a detailed introduction to the modification project of the freezing crystallization unit in the deep treatment process of mine water. It summarizes the application effects of the modification scheme. The implementation of this project has addressed issues such as poor freezing crystallization effects during the operation of the original process, frequent floating nitrate in the effluent affecting the salt purity of sodium chloride products, and the inability of facilities and equipment to operate continuously and stably.