The completion string is easily be bent due to its high temperature and pressure in the complex mechanical environment , which greatly affects the service life of the string. Based on the theory of elastic-plastic mechanics, A finite element mechanical model to analyze the buckling behavior of the tubing string under the actual well conditions was established , and the buckling shape is analyzed on this basis. lateral displacement of the tubing string under the complex mechanical conditions, and then the influence of the buckling measures of the tubing string on the buckling behavior of the tubing string are studied, such as adding centralizer, optimizing production and the design of expansion tube. The results show that under severe conditions, the bottom of the tubing string is prone to more complex buckling. The tubing string from 5500m to 7300m depth has a spiral buckling configuration, and the whole buckling section is 2400m . Under this condition, when the length of the expansion joint reaches 6m, the reduction rate of the length of the buckling section of the tubing string and the bending stress of the tubing string is greatly reduced, and the length of the expansion joint has a significant impact on the pipe . The influence of buckling and bending stress of columns is greatly weakened. For the gas wells, the control of production rate is the most obvious to improve the buckling behavior of the string in complex environment , followed by the centralizer design, technical support for improving the life of the string and the integrity of the gas wells is provided.