For the grid-connected operation of optical storage DC-microgrid, a system-friendly control strategy of optical storage DC- Microgrid is proposed. During the period of low voltage, the traditional photovoltaic works in MPPT state, and the energy storage works in constant voltage control method, which keep the DC bus voltage stable; When the energy storage approaches the limit while the bus voltage still can't be controlled, the photovoltaic needs to switch the operation mode. The method described in this paper is to control the DC voltage through the MMC at the outlet end of the optical storage DC microgrid. The output power of photovoltaic and energy storage is controlled by flexible control method, and its crossing ability is verified by RT - LAB. The experimental results show that when the AC system is 0.5 p. u., the control strategy can still enable the Photovoltaic cell to generate fully power, maintain DC voltage stability, and send reactive power to the grid to maintain network voltage, which verifies the effectiveness of the control strategy.