The invention discloses a 'two-zone' prediction method based on a blank box theory. According to the invention, factors of the thickness of an exploited coal layer, the property of the overlying strata and distribution states are taken as 'input' of the blank box; characteristics of surface subsidence states are taken as 'output' variables; the height of a water-flowing fractured zone is deduced and applied in an actual mine; the overlaying strata and surface subsidence caused by coal mining are complex processes; the overlaying movement limited by multiple factors is taken as the blank box system; through the overlaying strata moving blank box, discussion of the complex problems is avoided and prediction for the heights of 'two-zones' of the coal mine are achieved by use of the simple idea and method; and the actual coal mine geological conditions are introduced into the overlaying strata moving blank box model, the feasible value of the number of the assumed rock strata and the heights of the 'two-zones' are determined through the maximum subsidence, so the goodness of fit between the prediction value and the actual value is improved.