PDC bits are widely used in oil and gas drilling and geological exploration drilling. and good technical and economical results have been obtained. However，abnormal wear of the cutting element in drilling engineering affects the improving of technical and economic effectiveness of the advanced drilling method. Company Smith drill bit of Russia （Smith Bits） has developed a new cutting element， rotating around its inner shaft，inhibiting the wear of PDC cutting element. It is a new innovation and has practical significance. Prof Neskoromnyh V. V. et al have analyzed and researched on design and characteristic parameters of the bit with ONYX. Finished tests show， that the wear resistance of the ONYX is better than， that of the fixed PDC element. The result of drilling using such bit are better and the bits are being used actively in geological and prospecting organizations of Russia. It is worth for us to pay attention to.