As an efficient multi-core system structure, three-dimensional Network-on-Chips (3D NoC) opened a new filed of System-on-Chip (SoC) research. In this paper, we present an efficient routing algorithm for 3D NoC applications. This method is based on west-south-first routing algorithm and intra-layer routing has higher priority. We introduce the concept of possible deadlocked configurations and further loosen the sufficient condition of deadlock freeness in adaptive routing. By using channel dependency graph, the proposed method is proven to be free from deadlock. Furthermore, the proposed method can balance channel loads and reduce uneven adaptiveness effectively. Simulation experiments verify the theoretical analyses on adaptiveness and demonstrate routing effectiveness.