The invention relates to a 30-second cycle static analysis based electric power spot transaction security checking method, which comprises the steps that firstly an electric power regulation and control center receives spot transaction data sent by an electric power transaction department and performs online security analysis data preparation, then the regulation and control center performs static security analysis, and finally the regulation and control center provides a transaction center online stability control check result and an auxiliary service strategy. The method provided by the invention not only can improve the online security analysis capacity of a power grid, also can effectively deal with rapid changes of electric power spot transactions, thereby providing safe and stable running guarantee for development of the electric power market in China, and realizing coordination and unification of safe running of the power grid and orderly operation of the market.