Abstract: In order to reveal the characteristics changes of soybean adhesive in plywood hot pressing process， microscopic features of soybean adhesive in the simulated temperature under hot pressing process were studied by infrared spectrum analysis, and spectral characteristics of soybean adhesive from independent made, commercial purchase and pure soybean protein were compared. IR spectra showed that the peak had change in different location under different experimental conditions. The results of contrastive analysis and peak differential analysis showed that the second level structure of soy bean protein in commercial soybean adhesive had obvious change at 160 ℃ in the simulation hot pressing temperature, the thorough deformation of the soy protein was probably occurred, and no obvious change at 80℃.In addition, compared with the properties had no significant change in commercial soybean adhesive, while multiple characteristic peaks of soy protein had been changed in independent made soybean adhesive after treatment by urea.