Abstract: Acoustic emission system was used to obtain acoustic emission signals of fracture from plywood and chipboard specimen subjected by threepointbending. Two acoustic emission signals of cumulative energy and total ring counts were used to discuss the fracture process and characteristics of plywood and chipboard. By using amplitude and RMS, the process of internal fracture formation, crack propagation, appearance of macrocracks and rupture of plywood and chipboard was discussed with the increase of deflection. The results showed that internal damage evolution of wood based composites could be effectively characterized by parameters of acoustic emission signals, such as amplitude, RMS, cumulative energies and total ring counts. Fracture damage occurred earlier in chipboard than that in plywood, and damage evolution process of chipboard could be divided into two stages, that of plywood into three stages.