The present invention provides a construction method of a coordination layer in a software defined network (SDN) architecture, belonging to the technical field of computer application. According to the method, a centralized coordination layer, that is an OpenFlow coordinator, is added between a control layer and a forwarding layer, so that multiple SDN controllers in the control layer cooperate with each other to share service load of the control layer, therefore, an OpenFlow control flow is scheduled flexibly among multiple application heterogeneous controllers, the demand of a manger in an actual network is met, and the availability and reliability of the whole SDN system are improved.