Abstract: To well understand the impact of fractal cracks propagation on hydraulic fracturing, the fracture toughness expressions considering the fractal crack length and bending effects were re?derived based on traditional linear fracture expansion model, establishing a new equation for hydraulic fracture width and the model for crack internal net pressure as required by hydraulic fracture propagation. Theoretical analysis indicates that the fractal dimension increases with crack propagation bending angle. Compared with the linear fracture expansion model, the crack internal net pressure is increasing after considering the fractal crack length and bending effects, and the fracture width given by this linear model is decreasing in the first80%part of a fracture, that is, the fracture width near the fracture end could be increasing, which means that the fracture width computed by the linear fracture expansion model will be bigger than that in actual condition. Subsequently, the proppants available for fracture propagation in the linear model may possibly form bridge plugging in practice