To address how to deal with the interference problems of digital part of the drive caused by motor current spike pulse.A BLDCM control system which based on linear optocoupler’s current isolation sampling is designed.A sampling resistor is added between inverter circuit and ground to get voltage by current.By the amplify of linear optocoupler circuit

it is taken as the feedback signal of current loop.A software correction algorithm is designed for compensating errors caused by transmission.It has not only the function as isolation but also ensure sampling precision.The results of actual experiment prove the validity of this method.