Abstract: In order to solve the simulation problem of motor drag experiment，based on the idea of virtual simulation，using Unity3D technology，the motor drag simulation system based on Unity3D was realized． Through experiments，the system can accurately simulate the response of various electrical devices under different connection deployment conditions． The user can use this system to achieve initial experience of learning and simulation of the motor drag experiment． The system can complete some experiments that are not limited by time and space，which helps to improve the efficiency，accuracy，and safety of experiments，and reduce the cost of experiments．

Key words: Unity3D, motor drag, virtual reality