The invention discloses a submarine pipeline laying furrow opener, which is suitable for furrowing operation of a hard soil sand seabed with the water depth of 500 meters. The device comprises a drillbit, cutter teeth, a rotating shaft, a mechanical sealing piece, a nozzle, an outer shell, a push-pull rod inner rod, a push-pull rod outer rod, a fixing rod, a fixing clamping piece, a filter screen, a hose, an inner cylinder, an inner pump, an inner pump fixing base, a water inlet pipe, a water outlet pipe, a waterproof motor, a speed reducer and other components; the waterproof motor drives the speed reducer, so that the speed reducer drives the rotating shaft, the cutter teeth and the drill bit to rotate; the special top bifurcated drill bit is adopted, the soil breaking capacity is higher, a push-pull rod controls the operation angle and depth of the furrow opener, seawater pumped by the inner pump is pressurized by the nozzle, high-pressure water can crush hard soil and sand blocksand reduce the furrowing resistance, and the seabed is furrowed in a mechanical and hydraulic jetting composite mode. The submarine pipeline laying furrow opener provided by the invention has the advantages of being good in furrowing effect, high in working efficiency, stable in working state, economical, safe and the like.