When ultrasound propagates on the layered substrate, the phase and group velocities of surface wave are varied with the frequency, and dispersion which reflects properties of layered materials can be determined from the critical angles of surface wave for various frequencies. In the present work, broadband surface wave were generated by oblique incident, and wave reflected at the edge of specimen were detected by pulse-echo setup. Frequency components of detected signals were obtained by digital filtering, and Rayleigh critical angles were determined as a function of frequency. Three specimens with different coating thickness were interrogated and dispersion of surface wave was obtained. The leaky factors of surface wave were also considered. Results obtained in the present work show good agreements with previous works.