The bond performance and bonding mechanism were evaluated for a Konjac glucomannan (KGM), Chitosan (CS), and polyvinyl alcohol (PVOH) blended wood adhesive. An optimized experimental strategy was used to investigate the effects of the formula parameters of adhesives on the bonding strength of plywood using a Box-Behnken design and response surface methodology (RSM). The microstructure of the blended adhesives was analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). An optimum bonding strength (3.42 ± 0.31 MPa) was achieved with concentrations of KGM, CS, and 10% PVOH of 2.3%, 2.3%, and 5.0%, respectively. There was strong hydrogen bonding between the KGM, CS, and 10% PVOH adhesives and the interface. SEM observations indicated that the blended adhesive exhibited a net-like structure that increased the overall bonding strength. These results provided the scientific basis for the continual development of environmentally friendly wood adhesives and the improvement of processing conditions.