A concept of local congestion table is presented and a dynamic source routing (DSR) protocol is improved based on bypass, local congestion table and hello message systems. A routing protocol of congestion adaptive dynamic source routing (CA-DSR) is proposed. In the CA-DSR protocol agreement, a primary node can be aware of the network congestion by using local congestion table. When a congestion ... [Show full abstract] happens, the previous node of the congestion node on the primary route try can find a bypass path to go around the congestion node. When the data flow gets to the node with a bypass, they are distributed in the primary path and the bypass in proportion. As a result, it can realize the congestion adaptive function. The CA-DSR updates local congestion table by the hello message. The CA-DSR protocol can obtain less average delay from end to end, higher data delivery ratio, less normalized overhead compared with DSR. Simulation results show the advantages of CA-DSR protocol.