The synthesis of monoacylglycerol from the glycerolysis of soybean oil catalyzed by alkaline ionic liquid was investigated as an alternative to the industrial glycerolysis promoted on environmentally unfriendly inorganic base catalysts. 1-Butyl-3-methylimidazolium hydroxide ([Bmim]OH) has a low catalyst activity for the glycerolysis, attributing to the bad thermal stability. 1-Butyl-3-methylimidazolium imidazolide ([Bmim]Im) possesses a strong base strength and satisfactory thermal stability, and it exhibits excellent catalytic activity for the glycerolysis. By optimizing the main reaction parameter, such as temperature, glycerol/oil molar ratio, [Bmim]Im dosage, and reaction time, the results demonstrate that it is possible to achieve a monoacylglycerol yield of similar to 69% in the presence of [Bmim]Im at 200 degrees C, which is a higher value than those typically catalyzed by NaOH, KOH, Ca(OH)(2), or MgO at 240 degrees C (40%-60%). Furthermore, the recovery and reuse of [Bmim]Im were also satisfactory, and the catalytic activity unchanged even after recycling six times.