A method of manufacturing a semiconductor package substrate includes forming a trench and a post by etching an upper surface of a base substrate including a conductive material, filling the trench with a resin, removing the resin exposed to outside of the trench such that an upper surface of the post and an upper surface of the resin are at same level, forming a conductive layer on an entire area of the upper surface of the post and the upper surface of the resin, and forming a circuit wiring including an upper circuit wiring and a lower circuit wiring by simultaneously patterning the conductive layer and a lower surface of the base substrate.