The invention provides a semi-submersible platform. The semi-submersible platform comprises two floating bowls symmetrically arranged along the longitudinal medial surface of the platform, a plurality of stand columns located on the two floating bowls, and a deck box supported by the stand columns. Each floating bowl is symmetrical relative to the self longitudinal medial surface, wherein each of outer boards on the two side surfaces of the floating bowl and the longitudinal medial surface of the floating bowl form an included angle, so that the width of the floating bowl is gradually increased from one end to the other end. Each floating bowl is provided with at least two stand columns in the longitudinal direction of the floating bowl, wherein the center of each stand column is located on the longitudinal medial surface of the floating bowl, and the large end and the small end of the floating bowl are each provided with one stand column. The floating center of the platform is preferentially located in the positions of the large ends of the floating bowls in the longitudinal direction, the platform is suitable for serving as a crane platform and the like of which the end is provided with heavy mechanical equipment according to the demands of the engineering, the longitudinal distance between the gravity center of the platform and the floating center of the platform can be shortened, the weight of the platform is effectively reduced, the ballast water amount needed during platform lifting is reduced, the operation efficiency is improved, and the marine operation risk is lowered.