The utility model discloses a wafer positioning device, which belongs to the field of semiconductor device manufacture. The wafer positioning device is composed of a main controller (1), a motor control circuit board (2), a motor drive circuit board (3), a waveshape filtering circuit board (5), a veiling sensor (6) and a coded signal feedback device (7). Parameter values are input from a human-computer dialogue interface of the main controller to control the run mode and start-stop states of a coding motor, coded signals which are fed back by the coding motor is delivered to the motor control circuit board (2) through the coded signal feedback device (7), the signals are then transmitted to the motor drive circuit board (3) after analyzed and compared with the motor control circuit board (2), and the coding motor (4) is finally driven to rotate a wafer. Simultaneously, waveform change at the edge of the wafer is detected by the veiling sensor (6) and delivered to the motor control circuit board (2) after filtered by the waveform filtering circuit board (5), and gap positions of the wafer are detected when the filtered waveform change is fed back to the main controller (1) in the end.