The metastable phase equilibrium in the ternary system containing potassium, lithium and chloride ions was studied at 298.15 K using an isothermal evaporation method. The solubility, density and refractive index of the equilibrated solution were measured. The crystalloid forms of the solid phase were determined using a schreinermarks wet residue method. On the basis of the experimental data, the metastable equilibrium phase diagram and the physicochemical properties vs composition in the ternary system at 298.15 K were plotted. The experimental results show that this system is of a simple eutectic type system, no double salt or solid solution formed at 298.15 K. The phase diagram consists of one invariant point, two uninvariant curves, and two crystallization regions. The crystallization regions correspond to potassium chloride (KCl) and lithium chloride monohydrate (LiCl·H2O), respectively. Salt KCl has the largest crystallization field, whereas salt LiCl·H2O has the smallest crystallization field. Salt LiCl has strong salting-out effect on salt KCl.