As the microgrid contains large-scale flexible components，adoption of the traditional distribution network equivalent method for microgrid equivalence will bring about definite inadaptability to microgrid equivalent research.For this reason，the overall measuring and identification method is employed to investigate the equivalent model of microgrid，and a rational model structure considering the influence of the control strategy on the external characteristics of microgrid is presented.The parameters identification of the model is solved by the immunity algorithm.The proposed model is a non-mechanism model capable of better restoring the dynamic characteristics of microgrid.Finally，the effectiveness of the model is demonstrated via fault simulation.