In order to enhance the low-voltage ride capability of the twostage grid-connected system PV inverter based on Boost circuit，a control strategy with the DC bus voltage control loop based on Boost for LVＲT is designed in this paper． Firstly， the conventional Boost voltage control mode and output current control strategy of the twostage PV inverter are analyzed． A DC bus voltage control outer loop based on PV array maximum power point voltage feed forward is introduced to change the Boost voltage control mode． In this way，the purposes of making the DC bus voltage stable and preventing over current of the inverter are to be achieved． At the same time，the reference value of the active current is adjusted according to the voltage drop depth． On the premise that the inverter is not over current， the maximum reactive current is provided to help the power grid recovery． Finally，a 100kW PV inverter PSCAD simulation model is built to verify the proposed control strategy． The result shows that the method not only can suppress the DC bus voltage rise rapidly and effectively，but also can make the inverter provide more dynamic reactive power support for the grid even when the voltage drops．