Abstract: In the present study, the preparation feasibility of calcium propionate from eggshell by hydrothermal synthesis is first confirmed. The effects of solid-liquid ratio, reaction temperature and reaction time on the yield of calcium propionate were studied through single-factor experiment, and the optimum conditions were investigated by orthogonal experiment. The resuhs showed that the optimum conditions were as follows： solid-liquid ratio 1：20, reaction temperature 110 ℃, reaction time 6 h. Moreover, the yield can reach up to 92.57 % under the optimum conditions.