Abstract: A new emulsifier (SX-1) for emulsifying rosin ester was prepared from rosin as origin material. SX-1 could easily emulsify rosin ester with co-emulsifier without organic solvent. The effects of the primary factors on the properties of rosin ester emulsion, such as the quantity and way of addition of SX-1, the kind of co-emulsifier, the processing conditions in the inversion process were investigated. Thus, an aqueous emulsion of rosin glyceride,the stability of which was over 6 months at room temperature, was prepared with 8%(mass part) SX-1, 50% (mass part) rosin glyceride and water.