With the higher requirements for the safety and stability of traditional power grids, the energy crisis and environmental pollution problems are increasing. As a result, “Green” and “Low carbon” have become the urgent needs of the development of power systems. Based on the current situation, a multi-functional photovoltaic grid-connected inverter with power quality control is proposed. First, according to an improved adaptive harmonic detection method, the harmonic component in the grid-connected current is detected. Second, the command current is tracked and controlled by quasi-proportional resonance. Through the subjective and objective criteria importance through intercriteria correlation (CRITIC) game theory combination weighting method, a comprehensive evaluation model of power quality is established to evaluate the harmonic and reactive components. Third, considering the limited capacity of the inverter in practice, a capacity matching coefficient is formulated to compensate the dominating problems. Finally, simulation results show that the harmonic and reactive components are optimized and compensated in the grid-connection process of the inverter, which improves the power quality at the grid-connected point and greatly increases the utilization rate of the inverter. Therefore, the effectiveness and feasibility of the proposed strategy are verified.