Abstract: With the increasing penetration of distributed photovoltaic systems in low-voltage distribution networks, issues such as voltage fluctuations and insufficient reactive power support have become increasingly prominent. To address these challenges, this paper proposes a reactive power regulation method for photovoltaic inverters based on voltage sensitivity analysis and weighted optimization. First, a photovoltaic integration model for low-voltage distribution networks is constructed to analyze the coupling relationship between inverter reactive power and node voltages. Subsequently, a weighted optimization control model for voltage deviation is established to achieve coordinated reactive power allocation among inverter clusters. Finally, the proposed method is validated on a photovoltaic power station test platform. Experimental results demonstrate that the method effectively enhances system voltage stability and power distribution balance, thereby providing technical support for the safe and efficient operation of low-voltage distribution networks.