The development of offshore wind power in Taiwan is moving toward to the next step: to establish the demonstration wind farm before 2016. The aim of this study is to investigate the dynamic motion of the floating platform (semi-submersible type) in a wind-wave-current flume using a 1:50 scale model. The thrust force on the wind turbine was simulated by a solid disk with a diameter of 0.66m at present stage. Compared to the prototype, the elaborate scale model has only 2% error in geometric dimension, total weights and gravity position. The natural frequency and damping coefficient of floating offshore wind turbine (FOWT) was obtained from the free decay test. Different wave directions, wave environments, drafts, wind intensities, current speeds and combined wind/wave/current were applied to study the instability of FOWT and operating conditions. The six-degree-of freedom (DOF), accelerations and drift forces were measured to compare with model result and improve the existing design.