The invention discloses a vibration fault detection system and method for wind turbine generator units. Vibration data, including vibration data of front and rear bearings of a gearbox and vibration data of front and rear bearings of a generator, of all parts of the wind turbine generator units are collected through vibration collection nodes by setting up a wireless sensor network, routing nodes passing through all the units are transmitted to a network coordinator node in a multi-hopping mode and transmitted to a monitoring center in the distance through 3G, optical fibers and an etheric multifunctional network, and a negative selection algorithm based on mahalanobis distance is adopted for the monitoring center to achieve remote detection early warning of fault units and fault parts. The vibration fault detection system for the wind turbine generator units comprises the monitoring center, a detection terminal, a database server, the multifunctional network, the network coordinator node, the routing nodes and the vibration collection nodes. According to the system and method, efficiency of the algorithm is improved, the accuracy rate of fault diagnosis is improved, a large amount of time is saved, and the larger the data size is, the more apparent superiority of the algorithm is.