Abstract: The bottom trawling board has a special working environment when working close to the seabed. And it can also disturb the sediments when towing. This turbulence makes a kind of sand cloud effect. This effect and working conditions makes the hydrodynamic environment of the bottom trawling otter board is significantly different with mid-water trawling otter board.. This paper is aimed at understanding the hydrodynamic characteristics of the bottom trawling otter board in the flow field with the bottom effect and the sand cloud effect. We combines the numerical simulation method and flume tank experiment as our recearch methods. And we utilise oval cambered otter board as research subjects. In the study, we calculates and analyses the lift or drag coefficient and the lift-to-drag ratio in different bottom conditions and flow field mediums. The results show that both the bottom effect and the sand cloud effect of the flow field will have a significant impact on the hydrodynamic performance of the bottom trawling otter board. In the near-bottom conditions, the maximum lift-to-drag ratio of the otter board is significantly improved, but the corresponding angle of attack still remains at about 10°. When the dimensionless distance away from the bottom H/b=0.05, the maximum lift-to-drag ratio can reach about 4.0; when H/b=0.1, the lift coefficient reaches the maximum (about 1.3). The influence of the sand cloud effect on the lift coefficient of the bottom trawling otter board is more significant at the larger angle of attack (AOA≥30°), and the deviation value between the lift coefficient and the only-water medium gradually increases with the concentration of the mixture; the drag coefficient at each angle of attack (0°~50°) is higher than the only-water medium, and the deviation value of the drag coefficient gradually increases with the increase of the mixture concentration at the same angle of attack. Conclusion shows that the influence range of the bottom effect on the hydrodynamic performance of the otter board is about in the range of H/b < 0.5, and the lift or drag coefficient and lift-to-drag ratio of the otter board are also changed, while the sand cloud mainly effect lift-to-drag ratio of the otter board. This study aims to provide reference for the use and optimization design of bottom trawl otter board.