Abstract This paper mainly county power grid,for example,introduced a number of specific measures to use PSD-BPA flow calculation software for reactive power optimization analysis of power flow calculation method and conduct optimal adjustment of the results,and to optimize the results of the reactive power grid planning and construction role for a certain summary. In addition,the paper also introduces some simple knowledge about the county planning and reactive power principles,methods and steps county power grid planning and construction,with a view to planning for the construction of county departments and non-grid power optimization to provide a reference.