The laser-acoustic method is an effective tool for important material properties test. In the present paper, the surface acoustic wave (SAW) is applied in the nondestructive detection of subsurface cracks in metal. The study focuses on the dispersion of surface acoustic wave propagating in the layer with cracks. The finite element method (FEM) is employed by establishing a series of subsurface cracks models and a more real-like displacement load function is proposed to excite the surface acoustic wave. The subsurface cracks models are divided into 3 groups in depth and 3 groups in the separation distance to analyze the propagation properties of surface acoustic wave and influences of subsurface cracks on the phase velocity. The relation of phase velocity with the dimension of cracks in the frequency domain is investigated in the simulation. It is found that the finite element results fit very well with the surface acoustic wave theory and the dispersion curves in the frequency domain are very suitable to evaluate the properties of subsurface cracks in metal.