The invention discloses a turbo generator rotor interturn short circuit fault diagnosis method based on multi sensor joint. According to the method, a variety of fault characteristic parameters acquired by different types of sensors arranged at a number of parts of a generator and respective thresholds are used to carry out calculation, so as to acquire fault characteristic values when diagnosis is carried out according to each fault characteristic parameter; according to the reliability of different diagnostic methods, weight assigning is carried out on each fault characteristic value; the weighted sum of a variety of fault characteristic values is acquired; and finally by comparing the weighted sum with a comprehensive threshold, whether the turbo generator has a rotor winding interturn short circuit fault is identified. According to the invention, comprehensive analysis is carried out on the diagnosis information acquired by different types of sensors to judge whether the turbo generator has the rotor winding interturn short circuit fault; the method overcomes the shortcomings of the traditional single diagnosis method; and the sensitivity and the reliability of the rotor winding interturn short circuit fault detection of the turbo generator are improved.