Abstract: When the ultrasonic beam is used to detect the cylindrical workpiece by manual method, the ultrasonic field characteristics is very different from plane contact workpiece. The ultrasonic field changes because the ultrasonic probe is linearly contacted with the workpiece, leading to a large number of variation waves within its cross section. The waves include the longitudinal wave, transverse wave and wave propagating along the surface of the cylindrical surface wave. In this paper, by calculating and analyzing variation waves before the three bottom wave, the character and significance of the main variation waves can be well understood, thus providing more information for the integrated ultrasonic waves and helping to evaluate the internal quality of cylindrical workpiece.