In this study, a Buoyancy Preflex Method was introduced to enhance structural safety and performances for a large floating structure on which recently many studies are actively conducted worldwide. To demonstrate the effect of the Buoyancy Preflex introduced to the floating structure, an analytical study was conducted using parameters such as the ratio of the lengths of center modules to those of end modules. The analysis models for parameter were modeled into 5 cases, then a hydrostatic analysis on live load was selected from Equivalent Static analysis methods, then was conducted. The analysis procedure was divided into two steps, before and after live loading. As The result of this study, first analysis step, it was confirmed by each analysis model that excellent buoyancy preflexes were introduced. Even after the live loading, the 2nd analysis step, compressive stresses occurred at the bottom slabs of all analysis models, which enabled a determination that all analysis models can afford to secure safety and structural performance against live load.