An image stitching method capable of effectively decreasing an amount of sampling points is applied to a first monitoring image and a second monitoring image overlapped with each other and generated by a monitoring camera device. The image stitching method includes acquiring a first sampling point and a second sampling point respectively on the first monitoring image and the second monitoring image, detecting a first specific parameter of the first monitoring image and a second specific parameter of the second monitoring image, determining whether the first sampling point is matched with the second sampling point according to the first specific parameter and the second specific parameter, and deciding whether to stitch the first monitoring image and the second monitoring image by the first sampling point and the second sampling point according a determination result.