In centralized routing, routing tables are computed by a control platform, but routers do not make decisions anymore. It is necessary to build backup paths for each router so that packets can be forwarded after failure. Existing protecting routing schemes cannot work well in low-connectivity topology. To solve this problem, a method for building centralized protection routing is proposed in this paper. In this method, packets can be pushed back to the upstream nodes and sent by the backup paths of upstream nodes if current node has no valid paths after failure. The problem of building optimal protection routing for a given topology is proved to be NP-hard and a heuristic algorithm is proposed. The algorithm is verified in various topologies and the experimental results show that it is better than existing schemes.