The invention discloses a mechanical state identification method of a high voltage breaker, based on characteristic extraction and characteristic selection of a contact stroke curve. The mechanical state identification method of a high voltage breaker includes the steps: obtaining the contact stroke curve of the high voltage breaker in different mechanical states through a large number of breaking-closing experiments; calculating three core characteristics: breaking/closing time, breaking/closing speed and average speed; performing equi-width dispersion on the contact stroke curve, and taking the stroke values of each time as the characteristic points to form the characteristics to be screened; calculating the mutual information between each characteristic point to be screened and the fault category so as to represent the correlation between the contact stroke at the moment and the fault category; selecting a maximum correlation minimum redundancy criterion to screen the above characteristics, and selecting a group of optimal characteristic vectors; and using the screened optimal characteristic vector to train a support vector machine so as to perform state identification on the unknown state data. The mechanical state identification method of a high voltage breaker enables state identification to be more accurate and complete, and provides reference for analysis of the breaking/closing process.