A method for nondestructive evaluation of material constants of composite laminates is presented. An error function is established to measure the differences between the theoretically and experimentally predicted strains. The identification of the material constants is formulated as a constrained minimization problem in which the material constants are determined to make the error function a global minimum. A global minimization method together with a technique for normalizing the gradient of the objective function are used to solve the above minimization problem. The applications of the proposed method are demonstrated by means of several examples on the material constants identification of laminated composite cylindrical pressure vessels.