Carbon fiber (CF) as reinforcement, self-crosslinking carbon fiber/PMMA prepared by prepolymer method (CF/PMMA) composite. The fiber is then melt blended with PMMA matrix to prepare PMMA composite. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to analyze and characterize the composites produced. The results show that the composite material prepared by separately modifying the fiber with plasma, aqueous ammonia and HNO3 solution. The mechanical properties of the composite materials prepared by the modified fiber are improved, and the fiber and the PMMA matrix shows better compatibility.