The importance of utilization of ocean space is increased due to high population and narrow land space. The development of a new technology for future use of ocean space, such as a design technology of Very Large Floating Structures(VLFS) is needed. This paper introduces the rime history analysis of superstructures on very large floating structures and proposes the estimation method of time displacement history considering wave loads. The dynamic responses of superstructure according to variation of period and amplitude are analysed using an example frame structure and the dynamic structural safety of VLFS pilot superstructure is evaluated.