The invention discloses a deep-sea sediment continuous pressure maintaining coring submarine drilling machine. A sampling pipe manipulator, a plurality of spud legs, a derrick, a drill pipe manipulator, a pipe rack, a hydraulic system, hydraulic clamping pliers, a drill pipe clamping base and an underwater control system are arranged respectively on a base, and a main body frame in installed on the base fixedly; a plurality of groups of spud legs and pile shoes of the spud legs are arranged on the base, flipping oil cylinders are hinged among the pile shoes and the spud legs, and the inner side of the upper end of each of the spud legs is hinged with a lifting oil cylinder; and the pipe rack is arranged on the upper surface of the base, a pressure maintaining drill pipe and a sampling pipe are arranged in the pipe rack, and an underwater top drive is installed in the derrick. According to the drilling machine, the drilling machine is lowered into the seafloor through an armor of an offshore platform, after the machine is lowered into the seafloor in position, bottom sediments are subjected to low-disturbance drilling and continuous multi-section coring, at the same time, each section of rock cores are subjected to operation such as pressure maintaining processing, and the deep-sea sediment continuous pressure maintaining coring submarine drilling machine has the advantages of being compact in structure, reliable in working, small in volume, light in weight, high in working efficiency, low in disturbance and high in coring efficiency.