In this paper, we focus on the cross layer design of AODV (ad hoc on demand distance vector) routing protocol is implemented in Spatial-TDMA wireless networks. The routing discovery and routing maintenance strategies of AODV are simplified through the neighbor list kept by the Spatial-TDMA protocol. We select a Spatial-TDMA protocol called USAP (unified slot assignment protocol) and make some modifications of it. The cross layer design reduces the communication overheads and consequently obtains a higher network throughput. We implement this idea in the QualNet simulator and the simulation results show that the routing overheads and the number of route request messages sent by the nodes are reduced significantly. Meanwhile, it improves the network throughput performance.