We demonstrated theoretically the wave guiding of elastics waves in a two-dimensional (2D) phononic crystal (PnC) slab. The simulation model based on the Finite Element Method (FEM) was used to calculate the dispersion relation of unit cells that shows a complete band gap between frequency, f=312–412 kHz. The supercell technique to simulate two waveguides size shows filtering frequencies between 365-397 kHz within the band gap. We discuss the frequency shift of the wave guide as a function of the defect size for the possibility of elastic wave filtering application. `