The classical network architecture of current smart substation is introduced. The requirement on switch used in process level of smart substation is analyzed from several aspects， such as power supply， store-and-forward latency， temperature range， throughput， technology of zero packet loss under strong electromagnetic interference， self-healing time of ring network， multicast filter control and priority， and network security control， etc. A switch developing scheme for process level of smart substation is proposed， and the scheme is illustrated from aspects of design of net structure， hardware implementation and software implementation. The software structure and the role of various functional modules are introduced. Finally， test results and operation situation of the switch developed with this scheme are demonstrated and concluded.