During the last decade nonlinear Ultrasonics has advanced from being a laboratory curiosity, of little practical application, to a point where it is a viable technique for many manufacturing inspections. In this article, an ultrasonic measuring system designed specifically to make possible the study of nonlinear properties for the nondestructive evaluation of materials, and a power spectrum method used for measuring the nonlinear parameter β are illustrated. Some special capabilities not available in other commercial or laboratory instruments，such as high power RF tone burst excitatior for driving inefficient transducers, the high precision Super heterodyne Receiver for harmonics detection, and the easy parameter controls，are available in our equipment. Some factors impacting the performance of the measurement system are analyzed, and the linearity of the measurement system is verified. Some experiments are designed to evaluate the measurement validity of the system.
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