Abstract: The Static Synchronous Compensator (STATCOM) is an important component of the Flexible AC Transmission System (FACTS). Compared with traditional reactive power compensation devices, it has the advantages of being able to continuously adjust reactive power and having a fast adjustment speed. This paper first establishes the mathematical model of the three-level STATCOM. In response to the problem of variable switching frequency in the traditional hysteresis direct power control, based on the principle of "adjusting reactive power by amplitude and adjusting active power by phase", and using the three-level space vector pulse width modulation (SVPWM) as the basis, a frequency-fixed direct power control strategy based on the dual d-q coordinate system is proposed. Finally, a simulation model is built using MATLAB/Simulink to verify the feasibility and effectiveness of the direct power control strategy of the three-level STATCOM.