The invention discloses pharmaceutical salt refining technology. According to the pharmaceutical salt refining technology, natural bittern is taken as a raw material, first stage membrane treatment and second stage membrane treatment are carried out, double alkali method treatment is carried out, and at last evaporative concentration is carried out so as to obtain solid sodium chloride capable ofaccording with requirements in national pharmacopeia; original bittern is subjected to membrane penetration treatment directly, high cost caused by pH adjusting and cooling is avoided, and pharmaceutical salt refining can be realized at a relatively low operation cost.