The numerical wave flume is one of the main tools to research problems such as wave breaking
and wave-structure interactions in coastal areas [1]. However, the multiple reflections of waves
in traditional numerical flume reduce the accuracy and reliability of the model. Therefore,
absorbing wavemaker and sponge layer are put forward to absorb the secondary reflecting waves
from the wavemaker and the incident waves, respectively. The developed numerical model based
on is the smoothed particle hydrodynamic (SPH) method. SPH is a pure Lagrangian approach
which can handle large deformations of the free surface with high accuracy. In this paper,
Regular waves are generated by the wave-making paddle and absorbed by the sponge layer at the
end boundary. An absorbing wavemaker boundary condition is developed to absorb the second
reflecting waves from the wavemaker. The capacity of absorbing secondary reflecting waves and
incoming waves in absorbing wavemaker and sponge layer are validated through comparisons of
the numerical results with general wavemaker and solid boundary.