Abstract: The tension force varies significantly in the lifting process of the power catwalk, so, the tension variations and the maximum tensions in the lifting process are important factors in the catwalk's design. In this paper, the geometric equation in four different stages of the catwalk is established according to different boundary conditions, and the dynamics equations are established according to the D'Alembert's principle. A dynamics analysis software of the power catwalks is developed based on the dynamic model in four stages, using the C# to call Matlab functions. The tension variations in the lifting process of the designed power catwalk are analysed through the software, and the calculation results show that the designed power catwalk satisfies the functional requirements. The studies provides an important reference for the power catwalk's field application, a solid foundation for the power catwalk's structural design optimization and the performance improvement.