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Abstract: Deepwater drilling riser is the key equipment connecting the subsea wellhead and floating drilling platform. Due to complex marine environment, vortex-induced vibration (VIV) will be generated on riser, which will induce fatigue failure and even cause unpredictable drilling accidents. Therefore, it is important to study the VIV characteristics of deepwater drilling riser and reveal the main controlling factors for ensuring the safe and efficient operation of deepwater drilling engineering. In this paper, the VIV of deepwater drilling riser is numerically simulated in time domain based on the discrete vortex method (DVM). A hydrodynamic analysis model and governing equation of VIV is proposed with considering the effect of riser motion using DVM and slice method, where the governing equation is solved by Runge-Kutta method. Model validation is performed, which verified the correctness and accuracy of the mechanical model and the solution method. On this basis, the influence of the number of control points, current velocity, riser outer diameter, shear flow and top tension on the VIV characteristics of deepwater drilling risers are discussed in detail. The results show that with the increase of current velocity, the vibration amplitude of deepwater drilling riser decreases obviously, while the vibration frequency increases gradually. However, if the outer diameter of riser increases, the vibration amplitude increases, while the vibration frequency decreases gradually. The top tension also has great influence on the VIV of riser. When the top tension is 1.25 G, the VIV is suppressed to a certain extent. This study has guiding significance for optimal design and engineering control of deepwater drilling riser.