The present invention provides a low overhead multipath routing method of mobile ad hoc network. m non-intersected main paths are established from a source node SN to a destination node DN. Each main path has an equal length and equally comprises n middle nodes MN and n links. Except for the first hop node and the last hop node, each intermediate node on the main path can reach the destination node through the next hop node on k (1<=k<=m) different main paths. When the data is started to be transmitted, the source node SN selects a main path for data transmission. Each hop node is selected with a dynamic congestion control method, and finally the data message is transmitted to the destination node. The low overhead multipath routing method of the invention can be applied to the dynamic topology multi-hop network to establish a multi-path structure of network data transmission and has the advantages of increasing the path stability, reducing the frequency of routing halt between communication node, reducing the routing overhead of data message and increasing the transmission success rate of data message.