In response to the issue of low organic matter content in urban sludge and poor energy recovery efficiency through anaerobic digestion in China, a method has been developed by synergistically digesting urban sludge with easily degradable organic wastes (such as kitchen waste) to improve the buffering performance and nutrient ratio of the digestion material, enhance the digestion rate and organic load of the system, thereby improving the system stability and economic efficiency of energy recovery from anaerobic digestion of urban sludge. Through technological development, the relationship between different material ratios in synergistic digestion and anaerobic digestion performance parameters has been obtained, as well as key parameters for engineering design, which can provide support for industrial applications. Adding kitchen waste to the sludge helps significantly increase the gas production rate per unit volume based on the existing digester capacity. Small-scale pilot studies and medium-scale demonstrations have been completed, and a demonstration project is currently underway. National Science and Technology Major Project (Civil Sector) Important Technical Achievements Compilation (Volume 2) was experimentally verified at the Hefei Shiwulihe Sewage Treatment Plant. Currently, a demonstration project for urban sludge and organic matter combined biomass energy recovery - comprehensive resource utilization is being constructed suitable for urban sewage treatment plants. This technical achievement targets the typical characteristics of low organic content and high sand content in urban sludge in China, solving the common problems of low methane production rate and low degradation rate during anaerobic digestion. It can significantly improve the energy recovery efficiency of waste such as sludge from organic matters in China and reduce the cost of stabilizing and harmlessing sludge.