The hardness，gloss and water resistance of waterborne alkyd coating are poorer than those of oilborne alkyd coating，and improving these properties is of great significance for the promotion and application of waterborne alkyd coating. In this study，soybean oil，pentaerythritol and phthalic anhydride were used to synthesize alkyd prepolymers by alcoholysis，and isophorone diisocyanate（IPDI）was introduced to prepare IPDI-modified waterborne alkyd emulsion by phase inversion. The effects of IPDI and neutralizer AMP-95 dosages，and emulsification process on the properties of waterborne alkyd emulsion were studied. The results showed that when the amount of IPDI，AMP-95 and emulsifier was 50%， 0.6% and 5%，respectively，and the stirring speed was 4 000 r/min，the obtained waterborne alkyd film showed the better comprehensive performance with hardness of 2H，gloss of 90. 87， surface dry time of 2 h，and water resistance for 24 hours.