A package substrate is adapted to a ball grid array package. The substrate includes two substrate contacts, two solder ball pads, two via holes and two signal lines. A connection line of the two substrate contacts is substantially perpendicular to a connection line of the two solder ball pads. The two substrate contacts are respectively connected to the two via holes by the two signal lines. Each signal line includes a circuit trace section, an approaching section and a bifurcating section connected in sequence. The two circuit trace sections of each signal line are substantially arranged in parallel. The two approaching sections are substantially arranged in parallel and substantially symmetrical about the connection line of the solder ball pads. The two bifurcating sections are substantially symmetrical about the pad connection line and respectively electrically connected to the two via holes.