The invention discloses a data center network routing method based on a Fat-Tree structure, and belongs to the technical field of data center networks. The SDN technology is used by the method, the data stream size and the link transmission condition are comprehensively considered in a data center network of a Fat-Tree structure and having multipath transmission ability, and new streams entering the network are routed by using a dynamic load balancing (DLB) algorithm based on residual link bandwidth and the number of large streams; and after link congestion is detected, the large streams on the congested link are re-scheduled by using a dynamic re-routing (DR) algorithm based on deadline and switch queue length from large to small, until the link is not congested. By adoption of the data center network routing method disclosed by the invention, the load balance of data streams in the data center network can be realized, the routing strategy can be dynamically adjusted according to the network state, the utilization rate and the throughput of the link are improved, and the forwarding delay and the packet loss rate of the data streams are reduced.