AbstractTo evaluate the effects of preparation conditions of a 'green' soy-based adhesive (SBA), Viscozyme L was employed to hydrolyze the polysaccharides in defatted soy flour (DSF) for preparing SBAs, and plywood bonded by SBAs with Pinus massoniana veneer was then produced. Effects of enzymolysis pH, temperature, time, and additive amount of the Viscozyme L on water-insoluble substances content (WISC) and bonding strength (boiling-water test) of SBAs were investigated. Results showed that bonding strength increased first then decreased as enzymolysis pH and temperature were increased. WISC decreased with increasing pH and decreased first then increased as temperature increased. WISC decreased and bonding strength improved slowly with the increasing time. Bonding strength improved slowly as additive amount of Viscozyme L increased. WISC decreased as the added amount of Viscozyme L increased and then decreased slowly at the added amount of Viscozyme L of about 50 FBG and beyond. SBAs prepared by Viscozyme L action on soy flour slurry decreased WISC and improved bonding strength. The suitable preparation conditions of SBA for plywood are as follows: enzymolysis pH 5.2, temperature 50 oC, and time 20 min, and the additive amount of Viscozyme L depended on the application condition.