Pre-assembly method of large ship lift

The invention discloses a pre-assembly method for a large ship lift. The pre-assembly method comprises the following steps that S1, a ship lift platform is positioned; s2, ship lift platform expansion amount compensation is carried out; step S3, pre-assembling a main beam support; s4, butt flanges between the ship lift platforms are welded in a matched mode; s5, butt flange bolts are installed; s6, platform cantilever beam installation; step S7, boring a platform cantilever beam; s8, ship lift platform working positions are pre-assembled; s9, detecting the deflection of the main beam, the length and width of the platform, the overall flatness and the camber of the platform, and performing data analysis; and S10, after bolts are removed, packaging and transporting are conducted to an actual working point position, and during packaging, additional wrapping protection is conducted on the flange plate, the cantilever beam and the sliding wheel pin shaft. According to the invention, fulcrum support in an actual wo