The invention discloses a detection method for the energy storage margin of a micro-grid. The detection method for the energy storage margin of the micro-grid includes that detecting the energy storage margin of the micro-grid according to the load bearing ability change of the micro-grid before and after leading in an energy storage device, or calculating the needed minimum capacity of the energy storage device when the micro-grid would arrive at a certain energy storage margin; building a model based on a cost target, a renewable energy fluctuation inhibition target and a power demand matching target without the energy storage device, using an intermittent micro-power source as a decision variable to substitute into the model, calculating the model through a particle swarm algorithm, and recording the calculated capacity of the intermittent micro-power source and the comprehensive cost corresponding to the unit power load; using the energy storage device, using the capacity of the intermittent micro-power source and the capacity of the energy storage device as decision variables to substitute into the model, calculating the model through the particle swarm algorithm, and recording the capacity of the energy storage device at the moment and the comprehensive cost corresponding to the unit power load; using a bisection method to continuously regulate the load level of the micro-grid after using the energy storage device till arriving at stop conditions.