Abstract: The slim pipe string in well bore is a special structure inpetroleum engineering. In this paper, a dynamical model of rotating pipestring is proposed, with the consideration of the impact contact betweenrotating pipe string and well bore in any direction and at any point of welldepth and well bore circumference. The analysis is carried out using dynamicgap element, space beam element and Newmark method. The application to the B3-4-P31well shows that the rod string design can guarantee safe operation inwell bore and prevent the rod string from failure.