To solve the problem that the existing routing protocols of Ad Hoc network, which with high routing overhead or long delay, are not suitable to be applied directly to data-link networks, this article proposed a low-cost dynamic routing protocol for data-link networks. A real-time dynamic routing service is provided for the data-link members with little network overhead by embedding the routing message into the data-link networks runtime message. Experimental results verify the validity of the proposed routing protocol.