A water-soluble epoxy resin was synthesized by the reaction between novolac epoxy resin (F-51) and diethanolamine. Then, the modified F-51 was mixed with poly(alkylene glycol allyl glycidyl ether) as a film former of a sizing agent. A series of water-soluble sizing agents for carbon fiber (CF) were prepared. The modified F-51 was analyzed by Fourier Transform infrared spectroscopy. The surface morphology of the CF was characterized by scanning electron microscopy. The effects of the sizing agent on the handling characteristics were investigated by abrasion resistance, fluffs, and breakage and stiffness tests. The results show that the abrasion resistance of the sized CF increased by 114.5% and reached 2344 times and the mass of fabric hairiness decreased to 3.2 mg. The interlaminar shear strength (ILSS) test indicated that the interfacial adhesion of the composite could be greatly improved. The ILSS of the sized CF composite could reach a maximum value of 42.40 MPa. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39843.