The invention provides a method and device for evaluating an apparent water inflow of a coal seam roof and relates to the field of hydrology geology of a coal field and physical geography. The method comprises the following steps: determining a calibrated apparent resistivity data value corresponding to a burying depth of the coal seam roof at a drilled position; determining a calibrated actual water inflow of the coal seam roof at the drilled position; according to the relation between the calibrated apparent resistivity data value and the calibrated actual water inflow, determining an inflow relative coefficient of the coal seam roof; and determining the apparent water inflow of a position point of the coal seam roof in a region to be evaluated according to an acquired apparent resistivity value corresponding to the position point of the coal seam roof in the region to be evaluated and the inflow relative coefficient. With the adoption of the method and device provided by the invention, the water yield property of the coal seam roof of other positions except a drilled hole can be quantitatively predicated and evaluated, so that important reference evidences are provided for safety production of coal mines.