Abstract: Soybean oil polyols was synthesized from epoxidised soybean oil (ESBO) and methanol via a ring-opening addition process. The effect of various catalysts on ESBO conversion and polyols formation was investigated and the product structure was characterized by IR and ¹HNMR. HZSM-5 exhibits excellent catalytic performance in the transformation of ESBO into polyols due to the presence of Bronsted acid sites. With HZSM-5 as catalyst, the conversion of ESBO and hydroxyl value of the product polyols reach 92.4% and 177.4mg_KOH/g, respectively, at 140℃ and a reaction time of 16h.