The objective of this research is to develop bioplastic from soybean oil. Triglyceride-based copolymers were prepared from free radical copolymerization between acrylated epoxidized soybean oil (AESO) and methyl mathacrylate (MMA). AESO was synthesized by acrylation reaction with acrylic acid. Triethylamine was used as a catalyst and hydroquinone was used as a free radical initiator. The numbers of acrylate groups in soybean oil were determined by using the nuclear magnetic resonance spectroscopy (1H-NMR). Then AESO was copolymerized with MMA as a comonomer to form rigid polymer using 1 wt% of benzoyl peroxide as a free radical initiator. The mixture was cured at 90-100°C for 30 min in the oven. The effect of MMA content between 30-60 pph (part per hundred) based on weight of AESO was also studied. The transparent bioplastic, AESO-PMMA copolymer, are characterized by using the Fourier transform infrared spectrometer (FTIR) to confirm molecular structure. The glass transition temperature was determined by using dynamic mechanical thermal analysis (DMTA). The thermal resistance is analyzed by using thermogravimetric analysis (TGA). The tensile and tear properties were investigated as well.