Abstract: In view of cracking problems of cement after perforated completion,ball perforation and nailgun perforation on fiber cement are studied in this paper.Pore passage and rupture around pore passage are analyzed by electron microscope scanning and interpreted by fracture mechanics.The results show that there is destructive fracture on the non-fiber cement,while fiber cement can retain integral pore passage which contributes to perforation completion.After fiber cement is pounded by perforation,the fiber can absorb the shock wave and slow down the cement deformation,so the breaking strength will not be enough to the cement brittle rupture.It is shown that fiber cement has crack arresting affect on cleavage from the pore wall,and the fractional release G of critical energy is increased by coordinate bridging action which makes the inner section of fiber cement retains undamaged after completion of nailgun perforation.