In this paper, a three-phase buck-boost five-level inverter is proposed, which has advantages of a buck-boost function, a simple topology, easy control, less power switching components, and a low switching loss compared with the traditional multi-level inverter. The carrier cascade method is adopted as a modulation strategy for the inverter, and a PI regulator is used to control the system. In addition, the three-phase buck-boost five-level inverter and its grid-connected control strategy are simulated and verified based on the MATLAB/Simulink platform. Finally, the corresponding hardware experimental platform for the system was built, and the performance of the proposed circuit topology was verified by experimental results.