Rotor rub-impact fault may be diagnosed through several kind signal such as rotor vibration, stator vibration and rotor transient speed, and every signal include fault features of different side, so it is possible to improve diagnosis successful probability by mul-information fusing method. The fault identifying frame and combination diagnosis rules are determined using stator vibration and rotor transient speed signals. It is adopted to determine mass function by the S-function, and the deducing method is put up. After peak value of stator resonance demodulation and rotor transient speed fluctuation amplitude information are fused, the method is applied to diagnose rotor rub-impact fault successfully.