The trenching machine is applied to the trenching of underwater oil pipelines, with fast trenching speed, large depth, and relatively stable route. The trench blower is towed by a work boat for operation, and the top thruster maintains the working posture to prevent the trench blower from rotating in the water and causing cable damage; The high-pressure jet pump is driven by the underwater power pump station to break the soil, and the hydraulic thruster is used to form a trench.