The utility model belongs to the technical field of complex downhole accidents of a coal-bed gas well, and particularly relates to a special tool for refloating merging operation of a coal-bed gas well tail pipe. The utility model aims to solve the difficult problem that the lifting procedure is impeded by original phased operation sand burying, and provides a special tool for the refloating merging operation of the coal-bed gas well tail pipe. The special tool is of an integral step structure and comprises an end socket, a primary reducing head and a secondary reducing head of which the diameters are gradually reduced; female threads which are in matched connection with male threads of an oil pipe are arranged on the end socket; the primary reducing head and the secondary reducing head are of threaded structures; a plurality of water holes are uniformly formed in a transition rod between the primary reducing head and the secondary reducing head along the axis. The primary reducing head and the secondary reducing head of the special tool are respectively connected with a rock core sleeve, a tail pipe and a screen pipe; the operation procedures of lifting tubular columns and changing screw taps after sandblasting can be saved; the labor hour is saved; the secondary sand burying on the tail pipe after suspending sand is submerged can be avoided.