Abstract: The internal corrosion pipe specimens cut from the crude oil pipeline were analyzed by using theoptical microscope,X-ray diffraction analyzer and SEM energy spectrum analyzer.It was found that there existeddifferent types of hydroxy iron oxide as well as FeCO3and FeS in the corrosion products.The main causes of theelectrochemical corrosion perforation were discussed,and then the accelerated effect of stray electric current andchloride ion on the corrosion perforation mechanism was proposed,and further the protection methods against thiskind of corrosion were put forward.