In view of the complex situations of application environment and force condition of DTH hammer drilling with eccentric simultaneous casing, different boundary conditions and loads were set by the finite element models of DTH hammer drilling in the formation, and DTH hammer drilling simulation was made by the finite element software ANSYSY 12.0. Analysis was made on the stress-strain of the drilling tool in working conditions. Based on the simulation analysis and according to the drilling stress, theoretical basis for the design and optimization of DTH hammer drilling tool in structure rationality was provided.