Abstract: Defect categories and features of spiral seam cracking are studied based on spiral seam cracking facts in Northeastern Oil Pipeline Networks. Feasibility to apply ultrasonic detection technology to inspect spiral seam defects in the networks is analyzed from work principle and operating demands of ultrasonic cracks internal detector. It is considered that certain limitations are existed in applying the ultrasonic detection technology to inspect spiral seam to Northeastern Oil Pipeline Networks due to the influencing factors in ultrasonic wave emission, receiving probe and cleanness of pipe surface.