A non-contact new measuring method for torsional vibration of aeroengine rotor is researched, by making use of some kind of instruments like aeroengine speed measurement fluted disc and sensors. This method can be used for monitoring the torsional vibration of rotor based on the principle of that, the torsional vibration can cause the change of the width of rotate speed impulse and it can make the momentary fluctuation of rotate speed. The verification of this method has been done by experiment and numerical simulation. The results show that, this method can be used for monitoring the fluctuation of rotate speed caused by torsional vibration and the measurement of torsional vibration can be realized.