The key support technology of smart substation testing technology is analyzed, the concrete application of smart substation is combined with the traditional network testing, and the function of real-time network packet analysis is introduced, which has make the process of smart substation layer network test form a closed loop system, extend and improve the system of smart substation performance test. And links to the reality, to the transformer substation switchboard network storm suppression function, the time delay, lost projects and so on the frame rate to carry on the statistics, the contrast has confirmed this plan feasibility and the validity.