Vinyl ester resin emulsion type sizing agent (HMSA-1) was synthesized by phase inversion emulsification method. Centrifugal sedimentation analysis, particle size analysis, Fourier transforms infrared spectroscopy (FTIR), and gel permeation chromatography were used to characterize HMSA-1 and Japanese commercial sizing agents (JSA-1 and JSA-2). Meanwhile, abrasion resistance, fluffs and breakage, stiffness, scanning electron microscope (SEM) were used to analyze the workability in later process of carbon fiber and surface morphology. The results showed that HMSA-1 could significantly improve handling characteristics of carbon fiber. SEM micrographs demonstrated that the sized carbon fiber had smooth surface. HMSA-1 had better compatibility with vinyl ester resin. The interlaminar shear strength (ILSS) of HMSA-1 sized carbon fiber/vinyl ester resin composite reached the maximum value of 45.96 MPa. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012