A seamless switching control strategy is key to ensuring the stable and reliable operation of a DC microgrid. Such a control strategy for a DC microgrid from grid to off grid based on power compensation and droop coefficient attenuation is presented. This solves the problem of slow bus voltage recovery and poor power quality in traditional switching control methods. During island detection, the grid-connected converter works in the voltage control mode, and the energy storage converter (ESC) works in the droop control mode. Through modeling and analysis, it is proved that the DC bus voltage is controllable during island detection when droop control is used, and thus the selection method of the droop factor is obtained. After the islanding detection is completed, the ESC power compensation and droop coefficients are reduced by the fixed function to achieve a seamless switch of ESC droop control and voltage control. This prevents DC bus voltage fluctuations and ESC current impacts which may occur because of abrupt changes in ESC control mode. The selection method of the attenuation function is discussed. The simulation results show that the proposed seamless handover control strategy can effectively solve the problem of DC bus voltage being uncontrollable during islanding detection, and can suppress the current impact caused by ESC mode switching when islanding detection is completed. This work is supported by the General Program of National Natural Science Foundation of China (No. 52077010).