The 873 K isothermal section of La-Ni-Cr ternary system phase diagram was investigated by X-ray powder diffraction, differential thermal analysis and electron microscopy techniques. It is composed of 10 single-phase regions, 17 two-phase regions and 8 three-phase regions. At 873 K, the existence of ternary compounds has not observed in the isothermal section. The maximum solid solubility of Ni in Cr is about 3 at%Ni, and that of Cr in Ni, LaNi5, La2Ni7, LaNi3, La2Ni3, LaNi, La7Ni3 is about 35, 20, 15, 8, 9, 9 and 6 at% Cr, respectively. The solid solubility of Cr in the La7Ni16 phase is nearly zero.