Embodiments of the present invention provide a method and a device for signal processing in a spread spectrum system. The method includes: performing sampling and time-frequency transform on a received first time domain signal to obtain a first frequency domain signal; performing modulus operation on the first frequency domain signal with respect to a preset threshold to obtain a second frequency domain signal; performing inverse time-frequency transform on the second frequency domain signal to obtain a second time domain signal, and performing despreading on the second time domain signal. The embodiments of the present invention perform modulus operation with respect to the preset threshold on the first frequency signal obtained through sampling and time-frequency transform, to obtain the second frequency domain signal, can avoid the problem in the prior art that not only the NBI signal but also the SS signal which is a useful signal are filtered out, which results from frequency domain signals of a certain number of frequency points being set to zero, and thereby improve the reliability of signal reception.