Many surface ships are equipped with trunk structures to suspend the special equipment such as sonar and diving systems. The wall sat the trailing edge of the trunk will be impacted by the shear layer at the bottom of the trunk, while the fluid inside the trunk will slosh violently under the excitation of the external currents and waves during the ship navigation. Large slamming loads will be generated on the inner wall of the trunk by the sloshing motion of fluid. Aiming at this problem, the experimental tests are carried out to study the impact of the shear layer and the load of the fluid sloshing in the trunk. It carries out the analysis of the variation of the shear layer impact and fluid sloshing loads with the parameters such as the flow velocity and the opening form of the trunk. The regions with larger fluid sloshing loads are determined by comparing the test results at the different measuring locations in the trunk, which can provide guidance for the design of the trunk structure.