In order to avoid the complex mathematical operation and reduce the requirement of processor data storage space, a strategy for online fast estimation of switched reluctance motor (SRM) torque with magnetic commonenergy was proposed based on voltage chopper control. The measurement method of magnetic flux characteristics was described in detail, and the calculation formula of magnetic common energy and torque was given. The simulation and experimental results showed that the error of the instantaneous torque was small, proving that this method was suitable for the online estimation of torque.