In order to obtain the engineering constants of T800/QY9511 composites, by using finite element software ABAQUS and taking laser line source as force source, the process of pulse laser acting on the surface of the material and stimulating ultrasonic waves propagating inside the material was simulated. And the waveform was extracted from the center of excitation, 5 individual wave velocities were obtained. According to Christoffel theory of elasticity, the engineering constants were calculated. The results show that, compared with the real value, the average error of the numerical solution of elastic modulus is 1.56%. The mean error of Poisson ratio is 2.98%. The error of shear modulus numerical solution is 1.4%. Laser ultrasonic method is feasible and accurate in measuring the engineering constants of composite materials. It provides the basis for measuring relevant parameters in laboratory and engineering application.