A package substrate is provided. The package substrate includes a base layer having a first surface and a second surface opposite to the first surface, a plurality of through holes penetrating the base layer, a first metal layer disposed on the first surface, and a second metal layer disposed on the second surface. The first metal layer includes a closed-loop trench. A part of the second metal layer is electrically connected to the first metal layer via the through holes. The through holes are positioned at an inner part the closed-loop trench.