Abstract: The flexural properties of cement externally bonded carbon fiber sheet and aramid fiber sheet respectively were investigated by the three-point bending test.The surfaces of these two fibers were modification and the influence of surface modification of fibers on the flexural properties of FRP-cement systems was also discussed.The results show that the maximum load of CFRP-cement and AFRP-cement increases obviously after carbon and aramid fiber sheets were modified by plasma.Furthermore,peeling-off doesn't happen when the specimens were bended.The FRP is tensile fracture,which shows that high strength of the fibers works.