Lactic acid bacteria(LAB)were capsulated with alginate,gelatin and trehalose additive by extrusion method and dried at 4℃.The microcapsules were generally spherical and had a wrinkled surface with a size of 1.7±0.2mm.Trehalose as carbohydrate source in culture medium could reduce acid produce and had no function on positive proliferation of LAB.Using trehaiose as carbohydrate source and protective medium simultaneously had a benefit in protection LAB cells during the storage at 4℃,and the live LAB cells could be at l07 CFU/g after storage 8 weeks.Cells of LAB could be continuously released from the capsules from the acidic condition(pH 1.2)to the neutral condition(pH 6.8),and the release amounts and speeds of LAB cells in neutral medium were much higher and faster than that in acidic condition.Additionally,immobilization of LAB could improve the survival of cells when they were exposed to acidic medium(pH 1.2)by the survival ratio of 76%.