This study seeks to achieve rapid detection of the V-shaped crack depth on metal surfaces. To this end， this study investigates the action process of the V-shaped crack and the surface acoustic wave within a certain range and adopts the finite element method to simulate the transmission process of the surface acoustic wave signal excited by the linear pulse laser source in metal materials under the thermoelastic mechanism and the interaction process of surface acoustic wave and V-shaped crack. The study show that V-shaped cracks of different depths and surface acoustic waves have different interaction processes. By analyzing the mechanism of different depth cracks and surface acoustic wave， the crack depth information is divided to three range intervals， and the calculation method of corresponding crack depth is estimated. In accordance with different action processes， this study proposes a rapid judgment and detection method for the V-shaped crack depth on metal surfaces. By detecting the surface acoustic wave reflected echo signal RR and the converted shear wave signal RS peak size， the depth range of the V-shaped crack can be quickly judged， and then its depth information is detected. This method enables rapid location of the crack depth interval and improvement of the detection efficiency of V-shaped crack depth information on metal surfaces. The simulation shows that the error of the crack depth between the calculated value and actual one does not exceed 5%, and that this method can achieve efficient detection of metal surface V-shaped cracks.