The Ultra-high Pressure (UHP) and heat treatment are used to extend the shelf life of acidified milky beverage that contains IgG.The stabilities of acidified milky beverage and IgG in the beverage treated by ultra-high (static) pressure and heat were studied.The acidified milky beverage stability and IgG activity were influenced by various factors:pressure,temperature,treating duration and pH value of milky beverage.The viscosity of the acidified milky beverage treated by UHP was much higher than those treated by heat,but the water holding capacity of the former was a little less than that of the later; The shelf life of acidified milky beverage treated by pressure above 300 MPa was extended significantly.IgG lost its activity sharply when pH decrease from 4.5 to 3.5.The orders of the important factors affecting IgG stability were as follows:pH > pressure > duration.There are some IgG activities loss after UHP and heat treatment.For the same sterilizing effect,the IgG activity lost less after UHP treatment than that after heat treatment.