In recent years, nuclear power plant cold source safety accidents have occurred frequently, and the trash nets are important method to improve cold source safety. Most of the trash nets are installed inside the water intake channel or at the entrance to prevent trash from entering the pump room system. The trash nets are under the action of flow, waves, and wave currents, which inducing hydrodynamic force, the magnitude of the force is an important parameter in structural design. However, there are many types of trash nets, some of which have smaller mesh sizes, and it is necessary to systematically study their hydrodynamic characteristics. The experiments on different types of trash nets under the action of flow, waves, and wave currents are carried out in a wave tank, the hydrodynamic force is measured, the force characteristics and calculation methods of different types of trash nets is discussed. Under the action of constant water flow, the hydrodynamic force on different types of trash nets is proportional to the net rope drag coefficient, net projected area, and the square of water flow velocity, under the action of waves or wave currents, the maximum force on trash nets is also related to the square of the maximum flow velocity, but it is smaller than the force on the same constant flow velocity. When calculating the force on the sewage interception net under the condition of determining the flow rate, it is necessary to consider the increase of flow velocity caused by the proportion of trash nets area. When simulating a trash net, it is necessary to determine whether the Tanuchi rule is applicable through the Reynolds number of the net rope, and optimize the simulation method of the sewage interception net while ensuring similar hydrodynamic conditions.