Wafer aligning system and wafer aligning method

The invention discloses a wafer aligning system and method. The system comprises: a motion platform capable of translating around an X axis, a Y axis and a Z axis and rotating around the Z axis; a wafer object-carrying sucker supported on the motion platform; at least four cameras, wherein two cameras are respectively arranged in alignment with two opposite corners limiting positioning notches on a wafer so that the two cameras can obtain a target characteristic image of each corner, the other cameras are respectively arranged in alignment with other edges of the wafer so that the other cameras can obtain target characteristic images of other edges, and the fields of view of all the cameras are large enough to cover wafer transmission errors; a multipath image acquisition card which is coupled to each camera for acquiring the target characteristic images of the corners and the target characteristic images of other edges; and a processor which is coupled to the multipath image acquisition card for respectively comparing the target characteristic images of the corners and the target characteristic images of other edges with prestored ideal characteristic images and calculating the wafer transmission errors.