A multi-layer printed circuit board having a low noise characteristic, the multi-layer printed circuit board includes: at least one circuit layer; at least one isolation line for dividing the at least one circuit layer into at least two areas, the at least one isolation line forms an open pattern and the at least one isolation line extendedly forms a long neck line into the at least one area, and an internal opening of the long neck line located at a geometric center of the at least one area to improve the isolation, especially for the noises near the resonant frequencies of the isolation areas.