Abstract: With wood being considered as an orthogonal anisotropic material, itsfracture toughness KIC, denoting wood resistance against crack extensionis one of wood basic mechanical properties, with obvious anisotropy. Thetest results indicate that LTspecimen fracture toughness is obviously higher than that of TL, TR specimen;those of TL and TR specimen are close. Regardless of specimen types, crackpropagation all occurs at the crack tip. TL and TR specimen crack extensiondirection is consistent with the original crack direction, while LT specimen crack grows nearly parallel to the fiberdirection, The influence tendency of moisture content on each wood directionfracture toughness is about the same.