Abstract: Under the background of "carbon peak and carbon neutralization target", the utilization of new energy in China has made great progress, and the construction of a new-generation power system that adapts to the increasing proportion of new energy has become the primary goal. The characteristics of strong volatility and uncertainty of wind and solar power output bring new challenges of "difficult supply" and "difficult consumption" to the electric power and energy balance of the power system. The traditional power balance analysis model and method are difficult to adapt to the new-generation power system application with the increasing proportion of new energy. Therefore, this paper proposes a power and energy supply and demand balance analysis system for the new-generation power system with an increasing proportion of new energy. Firstly, the multiple uncertain factors of source, network, load, and balance resources in the new-generation power system are analyzed. Secondly, the calculation method of power and energy balance in the new-generation power system with the increasing proportion of new energy is discussed. Furthermore, the analysis method of power and energy balance and the risk early warning mode of supply and demand imbalance in new-generation power systems are summarized. Finally, the measures and suggestions for improving the power and energy balance analysis ability of the new-generation power system are put forward so as to provide ideas for the planning, operation, and simulation analysis of the new-generation power system in the future.