Abstract: In this paper,different blockage correction methods for the hydrodynamic performance of horizontal axis tidal stream turbine are analyzed based on numerical simulations and model tests. Five correction methods from published literature are obtained,and the correction results are compared with those in free-stream condition. Finally,blockage correction methods,which can accurately predict the hydrodynamic performance of tidal stream turbine in free-stream condition,are obtained. The results show that the wall effect has obvious influence on the hydrodynamic performance of the turbine. Power coefficients and drag coefficients in limited conditions are higher than those in free-stream condition,and the wall effect on power coefficients is gradually increasing with the increase of tip speed ratio. Due to the influence of blockage factor and tip speed ratio,the prediction accuracy of blockage correction methods is different;Pope and Harper correction results and Bahaj correction results are in good agreement with the performance of tidal stream turbine in free-stream condition. The research results provide a reference for numerical simulation of turbine’s hydrodynamic performance and engineering technology transformation.