Based on the control requirements of photovoltaic interface in the distributed DC power system， a control strategy for photovoltaic converter is proposed. Taking two-switch Buck-Boost converter for example， the control system structure for the converter is introduced and the small signal model is established. The operating principle is analyzed and how to select the close-loop control parameters is discussed. Finally， the control strategy was carried out on a 3 kW two-switch Buck-Boost converter. The experimental results show that the photovoltaic interface can work effectively to match the basic control requirements.