The invention provides a quick chirp modulation interference detection and suppression method for a direct-sequence spread-spectrum communication system. By taking full advantage of the characteristic that the data spectrum transmitted in a channel is similar to that of white noise in the direct-sequence spread-spectrum communication system, it is determined that a transient energy spectrum has high peak value and a time-frequency energy distribution plane must have obvious peak value lines due to the inference of a chirp modulation signal. The method comprises: at the receiving terminal of the direct-sequence spread-spectrum communication system, selecting several energy spectrum peak value points at different time on the time-frequency plane; roughly estimating a chirp constant and a rotation angle alpha of fractional order Fourier transform according to a linear rule; performing the fractional order Fourier transform (p=2alpha/pi) according to parameters; if an obvious peak value is detected, performing accurate search by using an iterative process, and performing wave-eliminating processing in a fractional order Fourier transform domain to suppress chirp modulation interference; and outputting the denoised signal to a subsequent processing process.