Fumaropimaric acid was synthesized and purified by reaction of rosin and fumaric acid, followed by the esterification with 2-hydroxyethyl acrylate, producing di-2-acrylate ethyl fumaropimaric ester (abbrev., AEFE). It was approved that the structure of AEFE has two out-ring C=C double bonds and a carboxyl group through a series of characterization methods (e.g., acid value, FTIR and 1H NMR, etc.). Then, AEFE was employed as reactive tackifier for modification of acrylate emulsion pressure sensitive adhesive (PSA) by in situ copolymerization, in which the effects of dosages of AEFE and emulsifier were investigated, respectively. It was found that the monomer conversion showed subtle decrease with increase of AEFE dosage, and the C=C groups in AEFE disappeared after copolymerization, indicating that AEFE had strong reactivity. Moreover, with the dosage of AEFE and dosage of emulsifier being 8.4wt% and 0.64wt% based on monomers mass respectively, the tackifier showed favorable compatibility with polyacrylate. Meanwhile, the modified acrylate emulsion PSA had the best adhesive properties as follows: the initial tack was 18# steel ball, the 180o peeling strength was 7.21 N/25mm and the holding force exceeded 100 h.