In this paper, a simple method to modify the poly(vinyl alcohol) (PVA) through ring-opening reaction of epoxidized soybean oil (ESBO), catalyzed by hydrochloric acid is reported. The effect of ESBO loading ratio, in terms of mole (PVA/ESBO (n/n) = 1:0.5; 1:1 and 1:1.5) in the reaction medium, on the biodegradable, wettability and thermal properties of final PVA-SBO films is systematically investigated, comparing with PVA. The formation of PVA-SBOs is structurally confirmed by Fourier transform infrared (FT-IR) spectroscopy, whereas their wettability and thermal properties are studied by water contact angle (WCA) measurement, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), respectively. The obtained PVA-SBOs with higher ESBO loading exhibit both improved thermal properties and higher hydrophobic characteristic compared to others. Furthermore, biodegradability of resulting PVA-SBOs is also investigated by enzymatic degradation experiments. It is determined that around 34% of PVA is degraded by enzymatic experiments after 30 days and PVA-SBO with lower ESBO loading is more degraded than others with around 52%. Consequently, some experimental results are presented to indicate that PVA-SBOs are encouraging materials for diverse applications and their extensions can be good candidate for reducing the environmental problem and consumption of petroleum resources.