Abstract: Ni-P coated carbon fibers were prepared by a chemical plating method. The microstructures of uncoated and coated carbon fibers were investigated by SEM and XRD, and the surface atom compositions were studied by EDS. The tensile strength of the carbon fibers was analyzed by a Weibull statistical method. Results show that the number of defects on the carbon fiber surfaces decreases after Ni-P coating. When the thickness of the NiP coating reaches 0.149μm, the tensile strength of carbon fibers exhibits a maximum value of 3.10GPa, a 8.77% increase compared to the uncoated carbon fibers, which might be ascribed to the elimination of a number of surface defects by the NiP coating.