The solubility of KCl and NH 4 Cl in water, 1-propanol and 5%1-propanol were determined by static analytical method. Based on the conjunction of static analytical method and titration method, the phase diagrams for 1-propanol–KCl–NH 4 Cl–water quaternary systems with different mass fraction of KCl and NH 4 Cl have been determined experimentally at 298.15K. Furthermore, the binodal curve data were satisfactorily correlated using a three-parameter equation. In the liquid–liquid–solid area of the phase diagram, the selective partition of KCl and NH 4 Cl has been studied. The effects of several parameters on the yield and the purity of KCl or NH 4 Cl in the precipitation were also investigated, such as different mass fraction of KCl to NH 4 Cl, the concentration of 1-propanol and temperature. The experimental results showed that the increase in the mass fraction of KCl to NH 4 Cl favored both the yield and the purity of KCl in the precipitation, and the purity of KCl is more than 98%, 95% and 91% when KCl/NH 4 Cl (w/w)=3/1, 2/1 and 1/1, respectively. The purity of NH 4 Cl is much higher only when KCl/NH 4 Cl (w/w)=1/3 and the purity can be >98%. The results also showed that low temperature favored the yield and has insignificantly influence on the purity of KCl. The increase in the concentration of 1-propanol favored the yield greatly, while the purity of the precipitation has a modest decrease.