Many rich - connected topologies with multiple parallel paths between servers have been proposed for data center net-works recently to provide high bisection bandwidth, but it re-mains challenging to fully utilize the high network capacity by appropriate multi - path routing algorithms. As flow - level path splitting may lead to traffic imbalance between paths due to flow size difference, packet-level path splitting attracts more attention lately, which spreads packets from flows into multiple available paths and significantly improves link utili-zations. However, it may cause packet reordering, confusing the TCP congestion control algorithm and lowering the throughput of flows. In this paper, we design a novel packet-level multi-path routing scheme called SOPA, which leverag-es OpenFlow to perform packet-level path splitting in a round-robin fashion, and hence significantly mitigates the packet re-ordering problem and improves the network throughput. More-over, SOPA leverages the topological feature of data center networks to encode a very small number of switches along the path into the packet header, resulting in very light overhead. Compared with random packet spraying (RPS), Hedera and equal-cost multi-path routing (ECMP), our simulations demon-strate that SOPA achieves 29.87%, 50.41% and 77.74% high-er network throughput respectively under permutation work-load, and reduces average data transfer completion time by 53.65% , 343.31% and 348.25% respectively under produc-tion workload.