A method and a device for calibrating PEEP valve are provided. The calibrating method comprises: obtaining a function between a control voltage value of the PEEP valve and a gas conduit pressure value of a breathing loop system according to a plurality of groups of different control voltage values of the PEEP valve and the gas conduit pressure values of the breathing loop system corresponding to the control voltage values adjusting the control voltage value of the PEEP valve according to the function in order to obtain an expected gas conduit pressure of the breathing loop system. By establishing a segmented linear plot of the function corresponding to the relationship between the control voltage and the gas conduit pressure values the method and the device can adjust the control voltage of the PEEP valve according to the segmented linear plot of the function thereby achieving precise control of the PEEP valve.
