The work aims to take basswood as the research object to study the fracture dissociation morphology and fracture mechanics characteristics of specimen under impact load and then establish a fractal fracture mechanics model suitable for fracture dissociation of wood raw material and describe its mechanical behavior in fracture dissociation. Impact load was applied to the basswood specimen, the morphology characteristics and fracture mechanics properties of the specimen were analyzed and the fractal fracture mechanics model suitable for the fracture dissociation of wood raw material was constructed. The transverse and longitudinal impact fracture of basswood specimen had fractal characteristics, but the crack shape and fracture morphology of transverse impact fracture were more complex than those of longitudinal impact fracture. The mean value for longitudinal impact fracture toughness of basswood specimen was 1.112 times that of the mean value of transverse impact fracture toughness. The mean values of transverse and longitudinal impact fracture dimensions for basswood specimen were 2.063 5 and 2.075 1, respectively. There was a linear positive correlation between the transverse and longitudinal impact toughness of basswood specimen and its fracture fractal dimension, and the goodness of fit was 0.778 7 and 0.812 2, respectively. The critical dissociation stress model of wood raw material fracture dissociation and the fractal fracture mechanics model of fracture toughness were also applicable to brittle materials. When the wood raw material dissociates under the impact load, the shorter the initial crack length of wood raw material, the rougher and more complex the fracture dissociation fracture, the greater the energy required for the fracture dissociation of wood raw material. The energy required for the crack to propagate along the direction of about 1.055 rad perpendicular to the direction of the impact load force is the smallest, and the wood raw material is most likely to be broken and dissociate along this direction.