Abstract: Crack is a general defect in the manufacture and operation of the pipeline, and it is harm to the pipeline. In order to raise the inspection accuracy of this type of defect, ultrasonic testing method was used with two methods such as echo amplitude and ADDT method to evaluate the crack quantitatively. The experiments showed that the echo amplitude method was suitable to evaluate the crack with depth less than 1.5 mm, and the ADDT method was suitable to evaluate the crack with depth more than 1.5 mm. With the increase of radial depth of the cracks, the errors increased for both method, but the error of the echo amplitude was larger. There were many factors related with the inspection accuracy, such as equipment, level of inspector and crack characteristics, and all the factors should be considered.