The alkaloid extracts of the inedible parts from the eggplant in food were investigated by the acteriostatic experiment and stability experimentS. The common ability of bacteria inhibiting nine kinds of common spoilage microorganisms, and the influences of the heat treatment, pH value, ultraviolet irradiation, the concentration of sucrose and NaCl concentration on it were also studied. The results showed that the extract had good antibacterial effect on yeast, bacteria and mould, and a significant bacteriostatic effect was better than that of 0.5% potassium sorbate; the thermal stability of the extract was good under the temprature of 121 ℃, while the bacteriostasis effect greatly reduced when the treatment temprature reached to 121 ℃. The pH and ultraviolet radiation also had a certain influence on the extract bacteriostatic activity, the optimum pH value was 7～8; the bacteriostatic activity was basically stable when ultraviolet irradiation in less than 30 min, and significantly decreased 30 min later. In additioncal, the antimicrobial activity of the extract increased with the increase of concentration of sugar or salt.