The invention provides a signal detection method and device, and relates to the technical field of signal detection. The method comprises the steps that the difference value signal of the signal to bedetected is acquired based on the preset difference value signal calculation rules and the acquired signal to be detected and then the adaptive threshold of the difference value signal is acquired based on the preset adaptive threshold calculation rules and the difference value signal; then the adaptive threshold and the difference value signal are compared, and existence of the disturbance signal in the signal to be detected is judged according to the comparison result; if the judgment result indicates existence of the disturbance signal in the signal to be detected, sliding window singularvalue decomposition is performed on the difference value signal so as to acquire the first sliding window singular signal of the difference value signal; and then disturbance information extraction isperformed on the first sliding window singular signal and the positioning result of the disturbance signal is outputted. Disturbance detection is performed through the adaptive threshold with combination of the mode of positioning the detected disturbance through sliding window singular value decomposition to realize disturbance detection of the signal to be detected so as to be high in accuracy,high in anti-noise performance, more sensitive and more effective.