Electrolytic production process for solar-grade Si utilizing liquid Si–Zn alloy cathode in molten CaCl2 has been proposed. Toward the establishment of the process, the behavior of liquid Zn metal was investigated in molten CaCl2 at 1123 K. The evaporation of Zn metal was largely suppressed by an immersion into molten salt, which enables the use of Zn electrode in spite of the high vapor pressure of Zn. The cyclic voltammetry suggested the reduction of SiO2 at 1.45 V vs. Ca2+/Ca on a Zn cathode. After the potentiostatic electrolysis at 0.9 V, Si particles with diameters of 2–30 µm were precipitated in the solidified Zn matrix by the slow cooling process of the produced liquid Si–Zn alloy. The alloying rate between solid Si and liquid Zn was measured as 4.56 μm s−1, and it linearly decreased with the Si content in liquid Zn phase.