Abstract: In UHV transmission line project, due to the requirements of insulation performance and mechanical strength, the weight and length of large tonnage tension insulator string are significantly higher than those of low-voltage line, resulting in a certain impact on conductor tension and stress sag in continuous gear. Therefore, in the engineering design of UHV transmission line, it is necessary to simulate and present the spatial attitude of tension string in the actual situation, so as to reduce the error of actual engineering and improve the refinement level of design. In the simulation research on the spatial attitude of large tonnage tension string of UHV line, the large tonnage tension string can be regarded as catenary distribution. In this paper, the catenary equation and the idea of micro element are used to solve the stress analysis of each component on the tension string, calculate the relative angle between each component, determine the spatial attitude of each component, and obtain the overall attitude of the large tonnage tension string.