In present paper, the fracture toughness and fracture behavior of Ti17 titanium alloy with basket-weave microstructure are studied. The results show that fracture toughness is attributed to two major contributions, namely the crack path tortuosity (extrinsic part) and plastic deformation work along the crack path (intrinsic part). Good plasticity and tortuous crack propagation path are both favorable to improve the fracture toughness of Ti17 alloy. Moreover, based on the power theory, a fracture toughness prediction model is built., which prediction error is within 6%. In addition, by analyzing the prediction results of this model, it can be found that the contribution of plasticity work to the fracture toughness of Ti17 alloy is the major part, which occupies over 80%. The contribution of crack propagation tortuosity to the fracture toughness of Ti17 alloy, however, is the minor part, which is within 20%.