The reflection and transmission characteristics of regular waves by a partially immersed curtain-type breakwater have been studied by the experiment and numerical model in the paper. Non-overtopping and overtopping of the breakwater by the incident wave were considered to compare different wave dissipation efficiencies. An incompressible Smoothed Particle Hydrodynamics (SPH) theory combined with a Large Eddy Simulation (LES) model was employed as the numerical tool. The SPH method is robust for tracking free surfaces without numerical diffusion and the LES model is capable of analyzing turbulence and eddy vortices during wave-breakwater interactions. A good agreement between computational and experimental wave profiles verifies the accuracy of the SPH-LES model. The computations also disclose that the wave energy dissipation is mainly attributed to the turbulence production and vortex shedding during the wave transmission and reflection processes.