Abstract: With the rapid increasing integration of photovoltaic (PV) power generation, power control of PV plant has become main research direction and research focus around the world. National standard “Technical requirement for connecting photovoltaic power station to power system” (GB/T 19964-2012) in China requests that PV plant must have the capability of reactive power and voltage regulation, and make full use of the ability of PV units to regulate their own reactive power to participate in voltage stability control of power system. This paper takes full account of the interaction between power grid and PV power plant, and proposes a multi-level reactive power control strategy based on sensitivity analysis for PV plant. Firstly, reference of reactive power is calculated combined with the analysis of reactive power and voltage sensitivity of PV power plant and the operation status of power grid. Secondly, reactive power command is allocated to each PV unit according to the reactive power margin. Finally, a reactive power control system model in accordance with an actual PV plant is established based on DIgSILENT PowerFactory platform to verify the correctness of the strategy proposed in this paper.