Emulsion type sizing agents for carbon fiber were prepared by phase inversion emulsification. Standing stabilization and particle size analysis measurements were used to characterize the sizing agents. Meanwhile, the processability and surface morphology of carbon fiber were investigated. The effect of sizing agents on interfacial adhesion of carbon fiber/resin composite was estimated by interlaminar shear strength(ILSS). The results showed that the sizing agent emulsified by polyoxyethylene nonylphenol ethers phosphate ester ammonium salt (NP-10 PA) and emulsifier 602 had good stabilization. The sizing agent could significantly improve processability of carbon fiber. SEM micrographs demonstrated that the sized carbon fiber had smooth surface. By adding epoxidized polybutadiene (EPB) and adjusting the ratio to epoxy resin (E-51), the flexibility of carbon fiber was ameliorated, the ILSS of composites was increased.