According to the theory of the critical refracted longitudinal wave (LCR wave) generation and stress measurement principles,a method is proposed to excite the LCR wave by the segmented sine signal,and a stress measurement is carried out by the cross correlation time delay estimation in this paper.Compared with the pulse excitation, the ultrasonic transducer can radiate sufficient energy at lower voltage using segmented sine wave,and there are fewer changes of LCR wave during propagation in the medium,so there is better accuracy of data processing.Experimental results show that the method can effectively measure the internal stress of the specimen.