A printed circuit board (PCB) includes two layers, two signal transmission traces, and a vertical interconnect access (via). The signal transmission traces are respectively arranged on the layers. The signal transmission traces are electrically connected to each other through the via. A centerline of the via with a vertical line of the layers form an acute angle θ, the angle θ is less than cos−1[(Lv2−Lt2)/(Lv2+Lt2)]. Wherein Lt is loss of the two signal transmitting traces in a unit length, and Lv is loss of the via in a unit length.