SDN (Software Defined Network) is the important part of Future Network, and the OpenFlow soft switch which separates the control plane from the data plane is the key instrument. In this paper, the OpenFlow switch are analyzed, the test experiment shows, (1) The OpenFlow switch of TCP/UDP throughput is almost the same as the load rate, when TCP/UDP packet load press is more than limit, lead to a large number of UDP datagrams in the OpenFlow switch buffer queue and eventually lead to overflow of opposites and are discarded; (2) With the incensement of the size of the packet, the throughput of the OpenFlow switch is increased, and the packet loss rate, the time-delay are reduced; (3) With the incensement of the transmission packet quantity, the throughput of the OpenFlow switch is reduced, and the packet loss rate, the time-delay are increased. The study shows the performance parameters of the SDN are load, packet size and the transmission packet quantity.