The invention belongs to the technical field of reactive voltage control of a power grid, in particular relates to a layered and zoned reactive voltage analysis method based on a boundary condition. The layered and zoned reactive voltage analysis method comprises the following steps of making the power grid layered and zoned; determining a researched zone and a boundary thereof; inputting maximum daily load, minimum daily load, output of a power generator, the boundary condition, a reactive compensation configuration condition and a limit value of a regional power grid; carrying out power flow calculation, adjusting reactive compensation capacity, and adjusting the boundary of the regional power grid to the boundary condition; judging whether an out-of-limit situation exists in the voltage in a region or not; and judging whether a power factor of each main transformer conforms to the stipulation of the limit value or not. According to the layered and zoned reactive voltage analysis method, reactive voltage correction and reactive voltage optimization can be fulfilled, the reactive voltage analysis efficiency of a large-sized power grid can be substantially improved, focused analysis can be conducted with regard to a local power grid, and the layered and zoned reactive voltage analysis method is suitably used for situations with relatively complete data of the local power grid and insufficient data of a large power grid; and the layered and zoned reactive voltage analysis method is easy to understand and implement, is proximate to actual running of the power grid, and is suitably for on-line application.