Unknown signal identification method and system in complex environment

The invention provides an unknown signal identification method and system in a complex environment, and the method comprises the steps: 1, obtaining an interference spectrum of the background noise of the complex environment through minimum mean square adaptive filtering, and achieving the tracking of the interference spectrum of the background noise of the complex environment; step 2, performing frequency spectrum shifting on the unknown signal through the measured interference spectrum of the environmental noise, so that the frequency spectrum of the unknown signal is in a frequency band lower than the amplitude of the interference spectrum of the background noise; step 3, the unknown signal after frequency spectrum shifting passes through a complex environment, after measurement and narrow-band filtering, a noise reduction signal is obtained by adopting a spectral subtraction method, and unknown signal identification in the unknown complex environment is realized; and step 4, repeatedly executing the step