The invention discloses a wafer jacking device and a jacking method thereof. The jacking method comprises the steps of: completing a first jacking stage by using first jacking assemblies, and driving jacking rod assemblies to ascend by means of miniature cylinders so as to jack a wafer, thereby separating the wafer and an electrostatic suction cup; and completing a second jacking stage by using a second jacking assembly, and further driving the miniature cylinders and the jacking rod assemblies to jack the wafer to a set distance by means of a cylinder. According to the wafer jacking device and the jacking method thereof, the first stage of the jacking process is realized by adopting the miniature cylinders, the jacking heights and jacking speeds of jacking rods are adjusted by means of the miniature cylinders so as to obtain the same jacking time and jacking force, the strokes of the miniature cylinders are short, the gentle and stable jacking process can be realized through reasonably controlling air intake amount of the miniature cylinders, the wafer is prevented from being damaged, the sizes of the miniature cylinders are small, the space is saved, the first jacking stage is realized by adopting the plurality of miniature cylinders, the second jacking stage is realized by adopting one cylinder, the jacking is more flexible, the cost is reduced, a helium gas does not need to be used, and the risk of contaminating the wafer is avoided.