The invention discloses a topping pressure-relief method for gob-side entry retaining. The topping pressure-relief method for gob-side entry retaining comprises the following steps that a chamber is excavated at the coal side of a gate roadway; a thousand-meter-scale directional drilling machine and a high-pressure water injection pump are installed in the chamber; a plurality of drill holes are drilled towards an open-off cut through the thousand-meter-scale directional drilling machine, and the drill holes are parallel to the gate roadway; the hole walls are cut with high-pressure water in the perpendicular direction when a drill bit retracts; the drill holes are sealed one by one through a hole sealer, the hole sealer is connected with one end of a high-pressure water injection pipe, the other end of the hole sealer is connected with the high-pressure water injection pump, and a pressure meter and a water injection valve are arranged in the middle of the water injection pipe; and water is injected into the drill holes through the high-pressure water injection pump. A through crack belt is formed between every two adjacent drill holes, directional cutting of a roof plate of gob-side entry retaining is achieved, the pressure and deformation of gob-side entry retaining are reduced, and tunnel supporting and maintenance cost are reduced. According to the topping pressure-relief method for gob-side entry retaining, explosives are not needed, drilling efficiency is high, manual labor intensity is light, conditions are created for gob-side wide entry retaining, the pressure and deformation quantity of gob-side entry retaining are substantially reduced, the entry retaining cost is reduced, and a good effect and broad practicability are achieved.