Considering limitation of taking energy consumption or cost index as the unique objective of power dispatch， this paper proposes an active/reactive coordinated optimization model for comprehensive energy saving of power system. In this model， the objective function is to minimize the total power generation cost and active power loss. By multiplier method， the multi-objective optimization problem is transformed into a single-objective one. According to the definition of optimal comprehensive benefits solution on Pareto optimal front set， the optimal solution of multiplier is obtained. For the proposed model， an approximate solution method and a method to deal with a system with network loss rate constraint are presented as well. This method provides reference for coordinating the conflict between total power generation cost and active power loss， and also for provincial power dispatch to transfer from traditional generation dispatching model to energy-saving generation dispatching model. Results of cases study on IEEE 30-bus and IEEE 57-bus systems validate the proposed model and algorithm.