Offshore fixed structure foundation negative pressure cylinder and installation method

The invention discloses an offshore fixed structure foundation negative pressure cylinder and a mounting method.The offshore fixed structure foundation negative pressure cylinder comprises an upper foundation structural frame and a negative pressure cylinder, the upper foundation structural frame is a truss type structural frame, and the negative pressure cylinder is of an inverted cup type structure with the bottom open and the upper watertight portion; a stand column of the upper foundation structure frame is connected with a supporting stand column of the negative-pressure cylinder in a welded mode, the negative-pressure cylinder breaks soil on the surface layer into a mud-water mixture through high-pressure water injection in the process that the negative-pressure cylinder is installed close to the bottom through a spraying pipe system, the mud-water mixture is sucked and discharged through a pump skid block, and the negative-pressure cylinder can conveniently and continuously penetrate till the top of th