Abstract. As always, the rapid wear of tools was one of the key factors limiting the precise turning of difficult-to-machine materials with diamond tool. 3-D elliptical vibration cutting has inherited many advantages of elliptical vibration cutting, such as the intermittent cutting property and friction reverse property. However, studies on the tool wear of three-dimensional elliptical vibration cutting has not been reported yet. The formation principle of 3-D cutting elliptical trajectory was analysed and a prediction model of tool wear was established in the present work. Besides, a self-developed three-dimensional elliptical vibration device was employed to conduct turning experiment. Compared with the proposed model, the experimental results showed a great agreement with the proposed prediction model. This work may provide a reference for the further optimization of the 3-D elliptical vibration cutting parameters.