Owing to the many advantages of carbon fiber, such as its high strength, good electrical conductivity, and light weight, carbon fiber-reinforced thermoplastics (CFRTPs) have been used in a variety of applications. However, the use of CFRTPs faces challenges regarding their manufacturing technology. CFRTPs have weak interfacial properties due to the non-polarity of carbon fibers and low surface free energy of thermoplastic matrix. Therefore, a key issue is the achievement of high interfacial strength between carbon fibers and the thermoplastic matrix. To achieve these goals, we proposed novel surface treatment methods for carbon fibers to improve the interfacial characteristics between the carbon fibers and the thermoplastic matrix.