Clamping and unclamping device is one of the most important composition parts on double-tube drilling rig. It is mainly used for drill pipe clamping and unclamping combined with the rotary mechanism, the stand or fall of its performance will directly affect the performance of the whole machine, drilling efficiency and quality. ABAQUS software has been used for the finite element analysis and optimization of clamping and unclamping device in order to shorten the development cycle and ensure the function and quality of the design. The results show that the optimized structure could meet the demands of safety factor, and could provide the guarantee to the reliability of the clamping and unclamping device and the integral performances of the double-tube drill.