The hydrodynamic model experiment results of trawling otter board often have different degrees of deviation due to various experimental factors such as Reynolds number and model scale ratio. To understand the Influence mechanism in the hydrodynamic model experiment of otter board, this paper selects vertical cambered V-Type otter board as the research object, bases on the flume tank model experiment combined with computational fluid dynamics (CFD) numerical simulation method, the hydrodynamic performance and flow field distribution were compared and analyzed, aims to explore the influence of model scale ratio, board thickness and model material on its hydrodynamic performance experiment. The results show that the change of model scale ratio has no significant effect on the curve shape of lift coefficient and drag coefficient, but excessive reduction of model scale ratio (20:1) will lead to significant deviation of lift coefficient at the small angle of attack (α < 30°). The change of the board thickness will lead to a significant change of the lift coefficient at the large angle of attack (α > 30°), while the influence on the drag coefficient mainly reflects on the small angle of attack (α < 30°). Non-metallic material model is insufficient rigidity, and it is easy to produce certain displacement and deformation after obtaining stress in the flume tank model experiment process, which will cause the deviation of experimental results. Based on the above results, the model scale should be as large as possible to reduce the influence of model scale on the accuracy of experimental results. The structure stability of the model can be improved by increasing the board thickness, but the thickening range should not be more than double of the prototype.