In various types of mechanical spindle drive, the torque is one of typical variables for reflecting the dynamic performance of mechanical system. By analyzing the torque, it can be available for the performance parameters of the whole drive system. There is no effective method for torque measurement under extreme environment, such as high temperature, strong impact, and strong vibration and so on. The paper brought out a new non-contact torque sensor, which adopt alternating electromagnetic induction ball grid technology, and was composed of specially designed ring-space arrays and dedicated magnetic detector. And it took emphases on the structure, principle of torque sensor. A simulation model was built to study the electromagnetic distribution characteristics of the detector by ANSYS. The experimental results verify that the detector can meet the dynamic torque measurement requirement in the extreme environment.