Along with the advance of science and technology in our country, the wastewater treatment technology in the chemical industry is also gradually increasing, various kinds of new technologies have been applied into the actual production, especially the nanofiltration technology. As a new separation technique, it not only can effectively treat chemical wastewater, but also can recover useful materials from chemical industry wastewater, so the nanofiltration technology has been widely used in chemical industry wastewater treatment. In this article, starting from the working principle of nanofiltration membrane separation technology, taking the salt chemical industry wastewater treatment as an example, the practical application of nanofiltration membrane was analyzed.