The utility model provides a mud sand-rushing device for maintaining a submarine pipeline, which can be used for rushing the mud sand when a submarine pipeline and a submarine cable pipeline are maintained, can effectively avoid the back settling, and can meet the construction requirement under the condition of large embedded depth. The device comprises a water supply pipe, wherein a gas supply pipe and the water supply pipe are fixed outside a mud discharge pipe; and the front end of the water supply pipe is provided with a nozzle assembly, the nozzle assembly is welded at the front of the mud discharge pipe, and the front end of the gas supply pipe penetrates through the nozzle assembly and is bent towards the inner of the mud discharge pipe. The gas supply pipe offers high-pressure gas, so that the mud sand is discharged to a far place through the mud discharge pipe, and the back silting can be avoided. The mud sand-rushing device is simple in structure and convenient to operate, a plurality of nozzles can be welded on the nozzle assembly, the mud sand-rushing device is high in rushing capability, the rushed mud sand can be discharged to the far place through the mud discharge pipe by the negative pressure generated by the high-pressure gas provided by the gas supply pipe, and the problem such as the back silting caused by rushed mud sand can be effectively solved. The large-embedded-depth pipeline can not be reburied by the rushed mud sand even if being rushed to remove the mud sand, so that the construction efficiency can be improved.