The invention discloses a time delay difference based multi-path transmission method in a data center network. A sending terminal allocates data packets dynamically for different paths according to path time delay and flow sizes; data packets that are sent earlier are sent to high time delay paths while data packets that are sent later are sent to low time delay paths, so that trailing flow implementation time is reduced. By adopting the method provided by the invention, available bandwidth of multiple paths can be used by a data center application in a more reasonable manner and flow implementation time is reduced, so that application performance is improved.