The utility model provides a composite apparatus fault positioning detection system which comprises a plurality of vibration sensors, a signal communication device, a host and signal emitters, the number of which is equal to that of the vibration sensors. Through collecting mechanical vibration signals of a composite apparatus in fault, the specific fault position of the composite apparatus is determined. The process where the vibration sensors collect the mechanical vibration signals is only related to response frequency of the composite apparatus and is not influenced by on-site electromagnetic field and sound wave interference signals, so that the problem of the influence of the on-site electromagnetic field and the sound wave interference signals in the fault testing process of the composite apparatus is effectively solved.