The invention provides a dual-motor four-bridge-arm inverter driving circuit and a magnetic field orientation control method thereof. The driving circuit comprises two star-shaped winding three-phasemotors, a three-bridge-arm inverter, a rotational speed and rotor position calculating unit, a rotational speed PI controller, a current coordinate transformation unit, a current PI controller, a voltage coordinate transformation unit, a space vector pulse width modulation unit, a PWM generation unit, a position sensor and a DC power supply. Each three-phase winding in three-phase stator windingsof the two motors is orderly connected to a midpoint of a four-bridge-arm inverter, the magnetic field orientation control method is used to obtain each three-phase reference voltage of the two motors, then a space vector modulation method is used to calculate nine switch trigger signals for driving the two motors, the signals pass the PWM generation unit to obtain power switch trigger signals ofthe four-bridge-arm inverter, and the effective control of the two three-phase motors is achieved. The dual-motor four-bridge-arm inverter driving circuit and the magnetic field orientation control method have the advantages of simple implementation, high reliability, fast response and high precision.