The V-type otter board is an important part of the single-ship bottom-trawl system. In order to explore the hydrodynamic variations of V-shaped otter boards in various working postures, we applied a numerical simulation method (computational fluid dynamics, CFD) to compare the hydrodynamic characteristics of the otter board with different aspect ratios (0.4, 0.5, 0.6, 0.7) and dihedral angles (16°, 19°, 22°, 25°), then selected one V-shaped otter board with superior hydrodynamic characteristics. Next, the hydrodynamic coefficient, surrounding flow field distribution, and surface pressure variation of this otter board were each analyzed in different positions of forward, backward, inward, and outward inclinations of 5°, 10°, 15° and 20°. The results show that: 1) the V-shaped otter board (No.13 otter board) with aspect ratio λ=0.7 and dihedral angle Γ=16° has the best hydrodynamic performance. The lift coefficient reaches its maximum value of 1.482 at 37.5°. The expansion efficiency reaches the maximum when the angle of attack is 10°. 2) With an increasing angle of attack, the pressure on the headstream surface of the No.13 otter board gradually increases, and the velocity difference between the headstream surface and the back flow surface of the otter board also increases. 3) When the No.13 otter board has different degrees of forward and backward inclination or inward and outward inclination, the lift coefficient decreases, and the drag coefficient decreases with increasing inclination angle. 4) With the increasing inclination angle, the pressure center of the headstream surface moves to the front of the otter board, and the change of the back vortices on the center of the otter board surface is not obvious. When the otter board is tilted back and forth, the pressure distribution of its flow face clearly changes; that is, with increasing inclination, the pressure center gradually moves up and down the front end, and the vortex of the otter board's center surface gradually decreases. The results of this study provide a scientific reference for predicting the variation of hydrodynamic characteristics of an otter board with different working positions and adjusting its stability.