The invention relates to the technical field of automobile power steering, and discloses an EPS-based motor drive axle control and diagnosis protection system. It includes a logic control unit, a drive axle management unit, a drive axle, an EPS motor, and a current sampling unit; the logic control unit includes a logic control module, a communication module 1, and an AD sampling module; the drive management unit includes a logic signal receiving module, a logic signal amplification module, communication module 2, current collection and processing module, motor phase collection and processing module, voltage collection and processing module and fault diagnosis module. The invention guarantees a certain driving ability when the voltage is low, so that the EPS can operate effectively, and the fluctuation of the power supply voltage is small; and the current sampling is carried out on the three-phase circuit of the motor, and the open circuit, short circuit and overcurrent of the motor phase are realized by diagnosing the current value Diagnosis of faults, etc., and can perform gate drive shutdown detection of each FET of the drive bridge, VDS monitoring of each FET of the drive bridge, and diagnosis of the short circuit of the drive bridge to the power supply.