Abstract: The floating wind turbine is easily influenced by wind, wave and current in the marine environment. A novel semi-submersible platform of floating wind turbine was designed. The numerical simulation hydrodynamic software AQWA combined with the finite element was used to analyze the motion responses of the novel platform in complicated marine environment by comparison with semi-submersible drilling platforms with three-column floating three-column structure and heave plate structure. The results show that the maximum and average values of the roll, pitch and heave response of the novel platform are significantly reduced in the frequency domain analysis compared with the three-column floating three-column structure platform, reflecting great stability of novel platform. The natural period of heave of novel platform is increased more than 2 times and thus it can more effectively prevent the occurrence of resonance phenomenon. In the time domain coupling analysis, the roll, pitch and heave motion response of novel platform significantly reduced, and the rolling and pitch motion response performance is more obvious; In the spectral analysis, the novel platform response spectrum peak is also significantly reduced, reflecting more superior wave frequency performance of novel platform. Therefore, the novel platform with great stability is reasonable and feasible and it can effectively suppress the swinging movement, providing a reference for design of floating offshore wind turbine platform in future.