Abstract: By testing the cold-rolled extra-low-carbon light gauge sheet samples under different deformation stages and observing them by SEM, their surface pattern and the rules of the transmutation of microstructure has been researched, and the mechanism of the formation of interior holes in gliding fracture was discussed. The result pointed out that it is dislocations' slipping and gathering in original impaired locations but not inclusion and second-phase pericles that is mainly responsible for formation of micro-holes in extra-low-carbon steel.