The present invention relates to the communications field, discloses a method and device for acquiring multi-frequency band digital predistortion (DPD) output signals, enables the result of DPD processing to compensate the intermodulation of multi-frequency band signal combinations after PA, and improves the ACLR of the signals after PA. Specifically, when performing DPD processing on an input signal received on a working frequency band, reference must be made to the DPD coefficients generated from the feedback signals of the signals previously received on the working frequency band and on other working frequency bands, and to the input signals currently received on other working frequency bands. In other words, intermodulation between the input signals received on working frequency bands are taken into consideration during the DPD processing work flow, so that the result of DPD processing can compensate the intermodulation of the multi-frequency band signal combinations after PA, and improves the accuracy of DPD processing, thereby enhancing the ACLR after wide band power amplification.