To reduce the dependency of the microgrid on communication system and implement plug-and-play for distributed generators(DG) and loads, the peer to peer control strategies in the microgrid were studied by considering the different operation modes. The droop control method of the DG was studied in the peer-to-peer control strategy. The voltage and frequency of the DG were regulated according to the linear droop characters of P-f and Q-U in the droop controller. The operation model of the micro-grid was established based on peer-to-peer control strategy. The operation characteristics of the micro-grid were respectively analyzed in three operation modes, concluding the load changes mode and the DG changes mode in islanding as well as the switch mode between the grid-connected operation and the islanding operation. With the MATLAB/SIMULINK simulation results, the changing laws of the bus voltage, power and frequency of the microgrid were studied. The correctness and feasibility of the peer-to-peer control strategy were verified with the simulation results.