Abstract: Integrated energy system is an efficient and energy-saving energy management mode, and is an important way to achieve the national "double carbon" goal. Focusing on the three core elements of energy flow, information flow and business flow in the integrated energy system, the relevant key technologies and development trends were systematically sorted out. In terms of energy flow, through multi-energy complementarity and intelligent scheduling, cascade utilization and efficient transmission of energy could be achieved to improve system stability. In terms of information flow, relying on artificial intelligence, big data and Internet of things technologies, the intelligent level of energy management was enhanced, and the ability to optimize energy efficiency and make decisions was improved. In terms of business flow, the energy supply and demand relationship was optimized through carbon trading market, demand response mechanisms and intelligent terminal devices to improve economy and sustainability. Integrated energy system needs continuous improvement in technical architecture and realization of collaborative optimization of energy flow, information flow and business flow. Meanwhile, it is necessary to further optimize the market mechanism, and promote the upgrading and development of integrated energy system towards low-carbon, efficient and intelligent direction.