The invention discloses a directional control device and a control method for a magnetic field of a permanent magnet synchronous motor. The device comprises a first adder, a first PI regulator, a subtracter, a second PI regulator, a Park inverse transformation device, an SVPWM device, a three-phase inverter, a permanent magnet synchronous motor, a position for feedback and a speed sensor which are connected in series; the device also comprises a second adder and a third PI regulator which are connected with the input end of the Park inverse transformation device in series; and the output end of the three-phase inverter is connected with a Clarke transformation device and a Park transformation device for feedback in series. The method comprises the following steps: extracting stator phase current; carrying out Clarke transformation; computing the sin value and the cos value of the electrical angle; carrying out Park transformation; carrying out PI regulation; carrying out Park inverse transformation; and carrying out SVPWM regulation. The invention realizes high precision, high dynamic performance and large scale control of the speed and the position of the permanent magnet synchronous motor through vector control.