The addition-esterification of epoxy resin and caproic acid catalyzed by acetylacetonate chromium (щ) was studied. The effects of temperature and the catalyst concentration on the reaction were investigated, and the catalytic ability was examined by comparing with tertiary amine and quaternary ammonium salt. And the reaction product was characterized by FT-IR and 1HNMR. The result showed that acetylacetonate chromium (щ) was a high-efficiency catalyst, with 0.4% of which the conversion of caproic acid could achieve 86.2% at 120℃. The reaction between epoxy resin and caproic acid was a second-order reaction, and the apparent activation energy (Ea) of the reaction was 142.668kJ/mol by kinetic calculations of the experimental data according to the integrated reaction rate equation.