The invention discloses a patching method of a sapphire substrate. A dispensing valve, a sliding rail, a digital display pressure regulating valve and a wax storage barrel are included. By means of the design method, a wafer is put on a sucker after being subjected to wax jilting baking, a wax drop is dripped at the center position of the wafer through the dispensing valve, and after the thicknessof a wax film at the middle position is increased, the wafer is pasted on a ceramic plate. The overall shape of the machined wafer is controlled by manually intervening the thickness of the wax filmunder the wafer, and the positive and negative BOW sorting action of the wafer can be omitted.