The invention discloses a separated filling entry retaining method for a sandstone roof medium-thickness coal seam. According to the method, the width of filling bodies is designed according to the stope geological conditions and the surrounding rock properties; the filling body intervals are determined according to the daily advancing condition of a working face; anchor rods are supported for supporting and protecting a roof in a roadway; a metal screen is erected for protection; the circle progress of roadway-side filling bodies is determined through being combined with the concrete production technical conditions of a mine; a separated filling mode is adopted for filling body filling; a separation plate is used between every two adjacent filling bodies for separation and sealing, so that the gob area air leakage is prevented. The separated filling entry retaining method has the characteristics that the safety and the stability are high; the filling construction engineering quantity is small; and the filling cost is low, and the like. The separated filling entry retaining method is applicable to the gob-side entry retaining mining of the medium-thickness coal seam under the conditions that the condition is the sandstone roof condition; the coal seam is more stable; the coal seam inclination angle is smaller than 25 degrees; the coal seam thickness in the gob area range is stable; and no great-fall fault exists.