Abstract: The integration of new energy into the grid has posed numerous challenges to the safe and stable operation of the power grid, and the task of ensuring power security supply has become increasingly severe. Spot market electricity prices can dynamically and intuitively reflect the power supply and demand situation, providing an effective guide for power supply security. Based on this, we propose an early warning level evaluation scheme for power supply security based on spot market electricity price forecasting. Firstly, a power supply security risk assessment mechanism based on spot market electricity price forecasting is proposed. Secondly, a spot market electricity price forecasting model utilizing the GARCHX-VaR technique is constructed. Power supply security risk is subsequently evaluated by assessing the electricity price warning levels. Finally, case simulation analysis is performed using data from a province in China that has already initiated a pilot operation of the electricity spot market. The results demonstrate that the proposed warning model is capable of effectively assessing power supply security risks, thereby providing robust support for power operating institutions in adopting appropriate strategies and measures.