The invention discloses an open-loop control starting method and device for a permanent magnet synchronous motor. The method includes the following steps that: the voltage command value of a dq coordinate system is outputted; the voltage command value and a counter electromotive force direction angle output by a counter electromotive force phase-locking unit are inputted into a pulse width modulation unit, and the pulse width modulation unit outputs PWM (pulse width modulation) signals for driving the switching component of an inverter unit; a three-phase output quantity outputted by the inverter unit is converted into a two-phase output quantity in a two-phase rotating coordinate system; and the three-phase output quantity and the counter electromotive force direction angle are calculated; and the PWM pulse signals are converted into a strong electricity voltage to control the motor. With the open-loop control starting method and device for the permanent magnet synchronous motor of the invention adopted, the magnitude and direction of the counter electromotive force of the motor in starting can be locked fast and accurately, and huge impact current generated by using open-loop control to start the motor when the motor is not stopped stably can be avoided, and a hardware detection circuit can be omitted.