With the development of smart grid technology，it is now more convenient for the implementation of demand-side response and the integration of all kinds of distributed energy resources.This paper first analyses the respective functions and coordination relationships of distributed generation，load and energy storage in the microgrid optimal operation，and regards them as the generalized demand side resources，then a more flexible optimization framework based on the concept ofsource-load-storage”is built up.In order to reduce the dimensions of the optimal operation problem，this paper then puts forward a solving model which combines the heuristic rules and particle swarm algorithm.The heuristic rules are used to generate the optimal strategies for storages and loads，while the multiple-objective particle swarm optimization（PSO）is employed to optimize the power resources.To achieve both stability and accuracy in the optimal control，the receding horizon optimization technology is adopted.Finally，the simulation cases with different combinations of various demand side resources taken into account are presented，showing the effectiveness of the method proposed.