Abstract: The prestressed slab with varying thickness using unbonded tendons was adopted in the floor structure of Wuhan World Trade Tower. The slab, with 1/52 height-span ratio, fixed at internal tube and outside frame tube structure. Using this type of slab, a more reasonable moment distribution can be obtained, and the floor weight is decreased with the increase of the space. The experimental study of the floor structure and the elastoplastic analysis method for the slab are addressed in this paper. Good agreement is reached between the enperimental results and those of the analysis.