The invention discloses a device for quickly stopping leakage of an underwater oil pipeline, wherein a first short section is connected with the oil inlet end of the underwater oil pipeline in parallel; a beacon is arranged in the first short section; the outer end of the first short section is provided with a seal head; the inner end of the first short section and the outlet of an oil transfer pump are respectively connected with an electrically operated valve; the oil outlet end of the underwater oil pipeline is successively connected with a second short section and an oil suction pump. In a normal oil transportation process, when an accident of outward leaking oil, which is caused by the sudden fracture of the underwater oil pipeline, is found, the working of the oil transfer pump can be stopped and the pressure in the pipeline is continuously reduced through ceaselessly pumping the oil by the oil suction pump; when the pressure in the pipeline is zero or a negative value, because of differential pressure effect of the front and the back ends of the beacon, the beacon moves forward along the oil; and in the mean time, the outward leakage of the oil at the fracture position of the underwater pipeline can be stopped along with the effect of the interior and the exterior differential pressures of the pipeline and water is ceaselessly poured into the pipeline though the fracture opening. By means of the device, the effect of quickly stopping leakage of a submarine pipeline can be realized and the serious environmental pollution and the economic losses which are caused by the massive leakage of the oil can be avoided.