Abstract: The present application provides an alignment method for backside photolithography process of the wafer, the alignment method includes: cutting the wafer, and using at least two edges formed by cutting as the first alignment mark; bonding the front side of the wafer to the wafer pad to form a composite wafer; aligning the first alignment mark with the corresponding second alignment mark on the photomask for backside photolithography. This method is not limited by wafer thickness and material, and reduces the secondary input of the photolithography equipment; meanwhile, the probability of fragments of thin wafers in the photolithography process can be reduced, and the yield of the product is effectively improved.