Abstract: With consideration of the special mooring system of floating offshore wind turbine and the deep-sea environment in which the grounding system is situated, taking into account both the effect of surge motion on incoming wind velocity and turbulence intensity, an three-dimensional wake model（3Dksg＿BP） is proposed on the basis of the two-dimensional BP engineering wake model in this paper, which is used to predict the transverse and vertical wind velocity profiles in the full wake region. The obtained results are compared with the measured data of the wind tunnel experiment, and it was found that the prediction accuracy of the downstream locations of 1.7D, 2.3D, 5.0D and 10.0D was not less than 97.6%. Based on 3Dksg＿BP, the effects of the surge motion on the wake at different frequencies and amplitudes are studied. The results show that the effects of the surge motion on the wake increase with the increase of frequency and amplitude, and the effects of the surge motion on the wake decrease with the increase of downstream distance.