The invention relates to the field of devices or methods for controlling a motor through vector control, and specifically to a device for detecting an initial position of a rotor of a permanent-magnetic synchronous motor and a using method thereof. The device for detecting the initial position of the rotor of the permanent-magnetic synchronous motor comprises a microprocessor (1), a current sensor (2), switch tubes and diodes, wherein a collector electrode of a first switch tube (31) is sequentially connected to a negative electrode of a first diode (41), a collector electrode of a third switch tube (33), a negative electrode of a third diode (43), a collector electrode of a fifth switch tube (35) and a negative electrode of a fifth diode (45); and the using method of the device for detecting the initial position of the rotor of the permanent-magnetic synchronous motor is characterized by comprising the following steps of: a, switching on and off the switch tubes; b, setting parameters; and c, calculating in the microprocessor (1). The device for detecting the initial position of the rotor of the permanent-magnetic synchronous motor has a simple structure, precise detection and strong adaptability.