The invention discloses a channel extractor and a software radio receiver using the channel extractor. The channel extractor of the software radio receiver of a corresponding frequency band is obtained at an output end through change of the decimation coefficient of a front-stage filter so as to realize flexible reconfigurability of channel extraction. The channel extractor consists of two stages:a preceding stage realizes reconfigurable decimation filtering, and is formed by cascading of an improved CIC (Cascaded Integrator Comb) filter and a compensation filter; and a backward stage realizes channel selection by a FIR filter. Through adoption of the channel extractor and the software radio receiver, the complexity is lowered through improvement on a new filter transfer function from theaspect of algorithm, and the software controllability of channel extraction is realized.