Alignment apparatus and method

The invention discloses an alignment device and method for aligning a substrate with a mask plat. The alignment device comprises a first closed coil, a first magnetic pole and a second magnetic pole, and a first current sensor, wherein the first closed coil is arranged in a first alignment region of the substrate; the first magnetic pole and the second magnetic pole are placed on two sides of a first predetermined region of the mask plate and generate a first magnetic field; gaps exist between both the first magnetic pole and the first predetermined region and between the second magnetic pole and the first predetermined region; and the first current sensor is connected to the first closed coil. The alignment device can improve the alignment precision.