Space wideband information network technology is one of the hot technologies in studying of space technology, there are many difficult technologies need to be solved, for example, technologies of the connection and communication between space and ground heterogeneous network, algorithm of mobile routing, etc. The paper does research on these problems based on IP technology of the ground network and CCSDS protocol that special for space communication, proposes an approach for communication between space network and ground network using IP over CCSDS mode, then it designs a data transmission configuration and protocol stack model for the space/ground communication network, in the end, the paper analyses how to perform mobile IP routing in the network and also puts forward method for multiple constrained QoS analysis in mobile IP routing network. As a result, the research work will accelerate the integration of the space/ground network and promote the cross-supports of the international spaceflight missions.