Abstract: Gate assignment is an important process in the course of CAD for printed circuit boards (PCB). In this paper we present an algorithm for gate automatic assignment (GAA) using first conjunction and secoud- conjunction. It has considered both the gates with same signal and the gates having same signal with another module. The algorithm can be divided into two parts: looking for Seeds and assigning gates.Besides GAA, we also use artificial assignment to enforee the agility, rationality and praclica lily.