When oilfield development comes to the end of waterflooding, the formation seeping features grows more complex. As a result, how to describe the variation of reservoir percolation characteristics comes to play an important role in making and adjusting a development plan. First, data processing methods for tested wells and construction methods for non-tested wells are used to interpret discrete single well monitoring indices data into continuous monitoring indices data for all wells in blocks. Second, based on the contribution, where continuous single well monitoring indices affects reservoir percolation characteristics, the system of block monitoring indices is established for describing evolution of reservoir percolation characteristics. The system of block monitoring indices consists of block absorbing capacity, block productive capacity, block liquid producing capacity, block seeping capacity and block pressure keeping level. In the end, evolution of reservoir percolation characteristics in YS Block of Dagang Oilfield is analysed by the system of block monitoring indices and acquires the same result as the developing fact of actual dynamical variance regulation. It is shown that the system of block monitoring indices in this paper can precisely describe evolution of reservoir percolation characteristics.