In the dual mode parallel / off network, the current distortion is caused by the abrupt change of the control command, and adverse effects on the power grid. However conventional droop control, although double mode problems are avoided, but it is a differential adjustment, also can produce a certain power fluctuations, affecting the stability of the grid. Therefore, based on the analysis of the above problems, this paper proposes an improved parallel / off line single mode switching control strategy, that is the output voltage amplitude, frequency and power of the inverter are pre synchronized before switching, in the switching process, the improved nonlinear droop curve is used to control. A smooth hand off from the network is achieved. The simulation results verify the feasibility of the proposed method.