Abstract: Software Defined Network (SDN) becomes a hot topic in recent years, in which flow update is one of important issues. In this paper, a classification based consistent flow update scheme is proposed, which has the advantage of strong generality and efficiently lightening working load on controller. The logic synthesis is also used to demonstrate how the scheme maintains consistency in the whole updating process. Simulation results in multiple scenarios show that the proposed scheme achieves better generality than existing schemes in related work. In addition, the scheme reduces significantly working load on controller while only costs nearly the same time in the update process as compared schemes.