Abstract-A novel solvent-free photosensitive polyester based on the hyperbranched aliphatic polyesters has been studied. The hyperbranched aliphatic polyesters (Polymer A), which was prepared from 2,2-dihydroxymethyl butyric acid(DMBA) containing one carboxylic group and two hydroxylic groups, Trimethylolpropane(TMP) and ptoluence sulfonic acid(p-TSA) as a catalyst, of which the degrees of branching (DB) was 0.53 according to definitions by Fréchet. Followed by end-modified with maleic anhydride(MA), end-modified hyperbranched aliphatic polyesters (polymer B) with unsaturated end groups was successfully synthesized. The properties of products were characterized by FI-IR, 13 C NMR, GPC, TGA,respectively. The UV-cured Polymer B based on polymer B, 4 wt% 1173 as photoinitiator, and Laromer R TPGDA(6:1) as reactive diluent was obtained, and was exposed for about 1s (2.2KW UV exposure apparatus). Therefore, the UV-cured Polymer B was obtained and regarded as a promising photosensitive material.