Utilizing the waste heat of exhausted steam in power plant as a new type of heat source is a key direction to achieve both energy-saving and clean urban heating. In order to recycle all the exhausted steam waste heat of multiple turbine units in designing condition, the authors' research group proposed a new cascade heating system with multi-heat source and applied it in several air cooling power plants in China. This paper focused on the system integration improving and operation strategy formulating, the main studies included: (1) Established the calculation model of system heating characteristics, and analyzed the problems about energy efficiency of system and safety of air cooled condenser in full operating conditions. (2) Introduced the "equivalent electricity of heating" as the evaluation method of comprehensive energy efficiency of the new co-generation heating system. (3) Improved the integration of heating system to further realize energy cascade utilization between turbine units. (4) Aiming at the improved heating system, the comprehensive optimization ideas of operational parameters in full operating conditions were put forward. By above methods, on one hand the "equivalent electricity of heating" of the new co-generation heating system is decreased by 16%, the comprehensive energy efficiency of system is improved, on the other the freezing risk of air cooled condenser is relieved, the operation safety of system is improved.