A printed circuit board assembly includes a printed circuit board, at least one electronic device, a holder and a heat-dissipation device. The printed circuit board includes at least one first through hole. The electronic device includes a first surface, a second surface and at least one pin. The first surface and the second surface are opposite to each other, and the pin passes through the first through hole of the printed circuit board and is inserted on the printed circuit board. The holder is disposed between the printed circuit board and the electronic device. The holder includes a supporting surface sustaining the first surface of the electronic device. The heat-dissipation device includes a heat-dissipation surface attached to the second surface of the electronic device.