Routing in Mobile Ad Hoc Network (MANET) is a challenge owing to the dynamic nature of network topology and the resource constraints. To maximize the channel resource utilization and minimize the network transfer delay along the path, the shortest path with the minimum hops approach is often adopted. However, the quality of wireless channels among the mobile nodes is time varying owing to fading, shadowing and path loss. Considering adaptive channel coding and modulation scheme, the channel state can be characterized by different link throughputs. If routing selection based on the link throughput is implemented, the minimum transfer delay from source to destination and the maximal throughput may be obtained. In this paper, a Channel Adaptive Shortest Path Routing (CASPR) is presented. Based on the adaptive channel coding and modulation, the CASPR transforms the link throughput into the channel quality factor Q and finds the shortest routing according to the Q measure. Simulation results show that the average path length in the proposed routing scheme may be slightly higher than that of the conventional shortest path with the minimum hops approach, but it can reduce the average transfer delay and increase the packet deliver rate.