Deformation and flexural response of consolidated Bamboo powder various particle sizes without chemical bond are investigated. In-Situ observation of the fracture toughness test is also performed to characterize the effects of such microstructural evolutions on crack initiation and propagation behaviors in the top of main crack. Maximum flexural strength was consolidated test piece made out Bamboo powder particle, P_<size>≦0.15mm. Mechanical properties, such as fracture strength σ_<max> and absorbed energy to failure E_<ab> are independent of Bamboo particle size. For Bamboo powder particle size is P_<size>≦0.032mm, there were degradation of fracture properties, remarkably E_<ab> and localization fracture view.