Abstract: For the purpose of lowering the signal sampling rate and reducing the amount of testing data, a sampling method of ultrasonic pulse signal with non-restrict finite rate of innovation (FRI) is proposed based on Hilbert transform. The pulse signal with FRI is obtained by solving the envelope of the tested ultrasonic signal using Hilbert transform. Then, low rate sampling has been accomplished on pulse signal. The adaptive capacity of the low-rate sampling technique is verified by putting additional Gaussian white noise in the signal. The experimental results show that this method can not only reduce the amount of sampling data, but also be used to estimate the arrival time of the echo peak accurately.