Base on the meticulous model of threaded bolt,one numerical method to research the dynamic response of structure with threaded bolt under pretension is presented. In the method,balanced penalty function method is used to deal with the thread contact problem,and the exponential pressure-overclosure is adopted. Pretension force is defined as a couple on the nut directly,since the helical model of the thread is obtained. Compared to the traditional pretension modeling method,it is not only simpler but also more reasonable. A method used to solve the static and dynamic coupling problem is presented,since the structure is under the static pretension force and the impact load synchronously. Firstly,the static response for the structure under pure pretension is analyzed. Then,the dynamic response is calculated taking the statically deformed state as the initial reference.For the mouth shape bolted structure,the numerical method presented in this article was used to study the dynamic response. The strain history of the thread bar was identical to the experiment results perfectly,and the maximal relative error of the pulse width or amplitude of the strain wave was less than twenty percent.