The invention discloses a method for predicting maximum height of a filling mining diversion fissure zone. Supposing a precondition that no caving zone is generated and only a fissure zone and a sagging zone are generated in the advancing process of a working face, a mathematical model which is used for predicting the maximal height of the filling mining diversion fissure zone; a critical value of top board deformation is used for determining the strata failure low of an over-limit stress limited space; and whether the strata fails is determined according to the critical value of the top board deformation. Therefore, compared with the prior art, the method has advantages of more direct calculation and higher convenience. A calculation formula for predicting the maximum height of the filling mining diversion fissure zone can be simply and accurately obtained. Furthermore the parameters in the formula can be easily acquired, and higher accuracy of the calculation process can be realized. Simple and direct calculation can be obtained. The method can quickly, effectively and accurately predict the maximum height of the diversion fissure zone and is suitable for guidance for actual production, thereby realizing safe mining under water body.