Aiming at the problem that at the peak of software defined network（SDN） data

the limited flow entry resources of SDN switches will have a great limitation on network performance

a dynamic timeout time optimization（DTO）algorithm is proposed. The algorithm estimates the number of new flow entry in the network in the next time period by dynamic exponential smoothing（DES）algorithm

at first.And then

dynamically optimize and adjust the stagnation time of the flow entry by dynamic parameters

according to the actual load status in the SDN.The simulation in Mininet shows that the optimization algorithm can effectively improve matching ratio of flow entry

the utilization of flow entry resources and the average network throughput

and improve the performance of the whole network.