This research analyzed the effect of nanocrystalline cellulose (NCC) on the thermodynamic property of soybean adhesive and verified the enhancement of the macro-bonding strength of soybean adhesive by NCC. The differential scanning calorimetry (DSC) and the apparatus of dynamic mechanical analysis (DMA) were applied to analyze the enhancement of the bonding strength of soybean adhesive by NCC and compare the bonding strength between blank soybean adhesives (the control group) and those added with NCC of 3% mass fraction. The DSC curves showed that the unfolding of soybean adhesive was a cooperative transformation accompanied with decalescence phenomenon in the range of 50~200 ℃ . The DMA curve of soybean adhesive illustrated that the addition of NCC resulted in the increase of the storage modulus E′ and the decrease of the dissipation factor tan δ, indicating that NCC improved the deformation resistance of soybean-adhesive plywood. And the test of bonding strength showed that the bond strength of poplar plywood was enhanced as NCC was added, and the bonding strength of samples added with 3% NCC was 56% higher than the control ones.