The invention discloses a gear fault diagnosis platform and a gear fault diagnosis method. On the platform, gear faults are simulated and vibration signals are collected, the improved local preserving projection algorithm is combined with a Bayes classifier, the mode recognition effect is judged according to the correct classification rate of the Bayes classifier, the vibration signals of the gear faults are measured by a vibration acceleration sensor, the principal component analysis is conducted firstly, and then, kernel transformation, construction of the nearest neighbor graph, solving of mapping space and the like are conducted; and the Bayes classifier is used for recognition in classification according to multi-fault classification. Compared with the principal component analysis, the laplace algorithm and the local preserving projection, the improved local preserving projection fault recognition rate can be greatly increased. According to the improved local preserving projection algorithm and the Bayes classifier combined fault mode recognition method, the fault recognition rate is increased and the accuracy is improved, and the effect of the fault mode recognition of the gear can be improved. The gear fault diagnosis platform has a simple structure, and a high-accuracy diagnosis platform can be provided for the fault recognition of the gear.