Embodiments of the present invention provide a method and a device for reducing intermodulation interference. The method includes: performing real-time estimation according to time domain information of M downlink transmit signals, to obtain a first intermodulation interference signal; and canceling, according to the first intermodulation interference signal, intermodulation interference generated by the M downlink transmit signals in an uplink receive signal, where M is an integer greater than or equal to 2, and the M downlink transmit signals are baseband signals that are transmitted on M carriers and that are not combined. Based on the foregoing solutions, first intermodulation interference obtained by performing real-time estimation on time domain information of M downlink transmit signals approximates intermodulation interference that is actually generated by the M downlink transmit signals in an uplink receive signal, so that the actually generated intermodulation interference can be effectively canceled, thereby reducing intermodulation interference and improving system performance.