Trim optimization is an efficient and easy method for ship energy saving and emission reduction. Without changing the depth of draft and speed of the ship, the ship’s navigation resistance is minimized by adjusting the trim Angle of the ship, and the ratio of the ship’s resistance to the required power is adjusted to achieve the purpose of energy saving and emission reduction. Taking a container ship as the research object, this paper adopts computational fluid dynamics (CFD) method and software STAR CCM + 20.0 to simulate the static water resistance value and self-propelled performance of the ship, utilizes multi-reference frame model (MRF) to process the rotating motion area of the propeller, and adopts VOF method to obtain the free liquid surface. Thus, the hydrodynamic performance of the ship is evaluated, and finally the trim optimization scheme and the shaft power of the ship under different trim and speed are obtained, which provides a basis for limiting the actual sailing power of the ship.