The invention discloses a permanent-magnet synchronous-motor open-winding fault-tolerant direct torque control method based on improved SVPWM. The method comprises the following steps of when an inverter switch tube has an open circuit fault, cutting off connection between a motor port and the fault inverter switch tube, connecting the motor port to a power supply midpoint, and using the remainingswitch tube to carry out fault-tolerant reconstruction on a system topology; through a PI controller, outputting a given torque; using a ''current method'' to estimate a stator flux linkage; and through the difference value of the given torque and an estimated torque, acquiring the variable quantity d delta of a load angle, using a maximum torque current ratio control method to give a reference stator flux linkage, and based on that, calculating a given reference voltage vector. Through the remaining switch tube, improved spatial voltage vector pulse width modulation reconstruction is performed. A double-inverter PWM control signal with a fixed switch frequency is output to an inverter. Under the open circuit fault of the switch tube, the safe and stable operation of a system under the fault is guaranteed, and the system has a good stable state and dynamic performance.