The output of PV is nonlinear, its output power changes as load, light intensity and ambient temperature changes. To improve the efficiency of photovoltaic power generation, we need to adjust photovoltaic cell’s output voltage or current with DC converter circuit. This paper analyzes the double-barreled Buck-Boost circuit, compared with the four common circuits, this circuit combines the advantages of Buck circuit and Boost Circuit, it can become buck or boost, the polarity of input and output are same, it has less passive components and low switching loss. This paper simulate the double-barreled Buck-Boost circuit with simulink, and made a real experiment, the simulation and experimental results show that the circuit can preferably apply to the DC/DC converter circuit of PV.