The characteristic that nodes can enlist into the network topology freely and independently without any fixed infrastructure makes mobile Ad Hoc networks (MANET) widely used in various environments such as disaster rescue, battlefield and so on. Traditional Ad Hoc network routing protocols are mainly based on the condition “Shortest Path”, and possibly form many local “hotspots” to influence the performance of the network. To this point, a new metric “Leisure Degree” is presented for denoting the transmission state of the node. Based on this metric, a cross-layer design method that involves the MAC (medium access control) layer and the network layer is used to present a new routing protocol Leisure Degree Adaptive Routing (LDAR), which uses a heuristic routing select mechanism to efficiently control the congestion and share the load. This method can improve the performance of the Ad Hoc networks. Simulation results show that LDAR performs much better than the DSR routing protocol under the circumstances of both static networks and mobile networks.