Ultraviolet (UV)-curable coatings made from acrylated epoxy soybean oil (AESO) combine the advantages of renewable biobased resources and energy-efficient UV-curable materials, so they serve as the primary research objects for developing eco-friendly coatings. However, due to the lack of rigid structure, the hardness and thermal stability of AESO are much lower than those of petroleum-based epoxy acrylate (EA). Therefore, high-performance soybean oil-based UV-curable oligomers were prepared by using dimethylolpropionic acid (DMPA) and methacrylic anhydride (MAAH) to modify ESO and then blended with high-functional active diluent trimethylolpropane triacrylate (TMPTA). Furthermore, FTIR, 1H NMR, and GPC were used to analyze the molecular structure and molecular weight of the oligomers. The oligomers (DMA/MAAESO and DMA/MAAESO-TM) had high esterification rate, curing degree, and good storage stability. The cured coatings from DMA/MAAESO and DMA/MAAESO-TM oligomers had significantly improved thermal stability, tensile, and coating properties. In all samples, DMA/MAAESO-TM cured coating had excellent coating performances. The glass transition temperature (Tg) of DMA/MAAESO-TM was 78.1°C, and its crosslink density (νe) was 6.87 × 10−3 mol/cm3. The hardness, curing time, gloss, flexibility, and impact resistance were H, 20 s, 108.5, 1 mm, and 50 cm, respectively.