The invention discloses a D-S evidence theory-based high-voltage circuit breaker mechanical fault diagnosis method.. The method comprises the steps of establishing a self-adaptive neural fuzzy inference system model; acquiring a sound signal and a vibration signal of the high-voltage circuit breaker; extracting characteristic quantities of the sound signal and the vibration signal; performing classification preprocessing on the characteristic quantity through the adaptive neural fuzzy inference system model to obtain a basic probability distribution function; enabling a D-S evidence theory modified by high conflict evidence to fuse a basic probability distribution function to obtain a mechanical fault diagnosis result.. According to the diagnosis method provided by the invention, the soundand the vibration signal are combined. The D-S evidence theory is used for information fusion to comprehensively diagnose the mechanical failure of the high-voltage circuit breaker, which improves the reliability and accuracy of the state assessment.