Abstract: Abstract：Due to the lack of Typical PV System Reactive Power Compensation Design Guide, at present the reactive power compensation capacity of PV power station in coal mining subsidence area is often estimated roughly in the?engineering application, which is easy to cause the adverse consequences of insufficient compensation or waste of design. In order to solve this problem, this paper explores an accurate calculation method for reactive power compensation capacity based on electric power flow analysis principle. This method, by means of calculating and analyzing the reactive power of each node of PV power station under the conditions of full-load and no-load of PV modules, can obtain an optimal configuration scheme of reactive power compensation capacity by integrating the power factor requirements of the grid. In order to verify the rationality of this method, this paper takes a PV power station project in a specific coal mine subsidence area as an example, applies the method introduced above for calculation and analysis of the project, and the PASAP software for a simulation calculation.