A printed circuit board (PCB) having vias for reducing reflections of input signals includes a first signal layer, a second signal layer, one via, an input signal line arranged on the first signal layer, and an output signal line arranged on the second signal layer. The via further includes a drill hole, a first pad, and a second pad. The first pad is electrically connected with the input signal line, and the second pad is electrically connected with the output signal line. An outer diameter of the first pad is smaller than an outer diameter of the second pad.