We present a laser ultrasonic method to investigate a titanium nitride (TiN) coating specimen. The techniqueis based on the principle of surface acoustic wave (SAW) dispersion during acoustic propagation on a half-space withthe presence of a thin layer. Due to the high efficiency of laser line-source excitation, we have been able to generateand detect a SAW with an excellent signal-to-noise ratio in a wide frequency band. An inverse fitting algorithm wasemployed to extract simultaneously the thickness and the elastic parameters of the TiN coating from the experimentalSAW velocity dispersion curve.