Focusing on the microgrid based on droop control, this paper designs a simulation model of mirogrid on Matlab/Simulink. The influence of inverter control parameters and load change on the interconnection transient process is analyzed, the concept of “load power benchmark” is proposed, the normal operation of the microgrid in island and the best interconnection load power range is determined on the basis of a large number of simulation data, which provides important reference from smooth interconnection of microgrid.