The printed circuit board comprises two first signal traces, a first grounding layer, two first signal traces, a second grounding layer, two signal conductive pillars and two grounding conductive pillars. The first signal traces are formed on a first surface of a substrate. The first grounding layer is formed on the first surface. The second signal traces are formed on a second surface of the substrate. The second grounding layer is formed on the second surface. The signal conductive pillars are extended to the second surface from the first surface and each signal conductive pillar connects the corresponding first signal trace and second signal trace. The grounding conductive pillars are extended to the second surface from the first surface and each grounding conductive pillar connects the first grounding layer and the second grounding layer. Each grounding conductive pillar and the corresponding signal conductive pillar are disposed in pairs.