Under the background of energy transformation,the development and utilization of demand-side resources will play an increasingly important role in ensuring safe supply of electricity, promoting development of the new power system, and contribute to achieve“dual carbon”goal. However, there is currently no systematic quantitative measurement method of its huge value, making it difficult to fully incorporate demand-side resources in power system planning. A demand-side resource value calculation method is proposed based on production simulation and sub-sectoral output value unit consumption, which can calculate the value of demand- side resources on power supply side, grid side, and user side. This method measures the value of demand-side resources within the scope of State Grid in 2025 and 2030, and analyzes the corresponding economics. By 2025, the installed capacity of new energy can be increased by 8 million kW, the maximum peak-valley difference ratio can be reduced by 4.6 percentage, the cost of users can be reduced by 40 billion yuan, the total investment of energy storage can be reduced by 60 billion yuan, and the carbon dioxide emission can be reduced by 800 million tons. Compared with new power plants, the annual income can reach 28.7 billion yuan.