The phase diagram of the CaInSe₂–CaIn₂Se₄  system is studied using differential thermal analysis, X-ray diffraction, mikrostructural analysis and mikrohardness and density measurements. It has been established that the system is a nonquasibinary part of ternary Ca–In–Se system. At room temperature the CaIn₂Se₄  based solid solution extends to 7 mol. % CaInSe₂, but on the CaInSe₂ the solubility wasn’t found aut practically. Compounds CaInSe₂ and CaIn₂Se₄ form the eutectic containing  25 mol. % CaIn₂ Se₄ which melts at  600⁰C