The invention provides a drilling method for a printed circuit board (PCB). The method comprises the following steps of: 1, providing a PCB to be drilled, and determining drilling depth of a front surface and drilling depth of a back surface according to the thickness of the PCB; 2, providing a cover plate and a drilling cutter, and determining the length of a blade of the drilling cutter according to the drilling depth of the front surface and the drilling depth of the back surface of the PCB and the thickness of the cover plate; 3, determining a coordinate system for drilling on the front surface of the PCB, drilling positioning holes on the front surface of the PCB, arranging the cover plate on the front surface of the PCB and fixing the PCB and the cover plate respectively; 4, drilling through the cover plate by using the drilling cutter, drilling from the front surface of the PCB to form a half hole according to the drilling depth of the front surface of the PCB, and then feeding the PCB; 5, inverting the PCB, determining a coordinate system for drilling on the back surface of the PCB, drilling positioning holes on the back surface of the PCB, arranging the cover plate on the back surface of the PCB and fixing the PCB and the cover plate respectively; and 6, drilling through the cover plate by using the drilling cutter, drilling from the back surface of the PCB to be communicated with the half hole to form a through hole according to the drilling depth of the back surface of the PCB, and feeding the PCB. In the method, a short-blade long drilling cutter is used for drilling from the two ends of the front surface and the back surface of the hole respectively, so a thicker PCB can be drilled through; and the method has the advantages of lower cost, higher drilling position accuracy and difficulty in breaking the cutter.