In order to analyze the impact of ambient temperature on the temperature field and long-term deformation of steel-tube-confined concrete-filled steel tube (TCFST), a temperature field analysis model of TCFST were established with ABAQUS finite element software. Taking the Shenzhen region as a case study, the temperature field of exposed TCFST columns under ambient temperature in the Shenzhen area were studied theoretically. Six TCFST short columns (with total steel content of the inner and outer steel tubes at 5.8%, 10.5%, and 15.0%, and a steel ratio of 0.75 between the inner and outer steel tubes) were designed and loaded under sustained axial compression for 850 days at room and changing ambient temperatures. The development law of long-term deformation of TCFST was clarified. Based on three commonly used long-term deformation prediction models for plain concrete, the long-term deformation of TCFST at room temperature was calculated. Real measurement data were used to modify the EC2 model for predicting long-term deformation of plain concrete, establishing a predictive model for long-term deformation of TCFST columns that accounts for temperature effects. The results indicate that when the average annual temperature of the section exceeds 20 ℃, it is advisable to consider the influence of temperature when calculating the long-term deformation of TCFST. The long-term deformation of TCFST columns decreases with an increasing total steel ratio of the inner and outer steel tubes, a higher ratio of steel content between the inner and outer layers, and lower temperatures. Additionally, the steel content of the outer steel tubes and season initial loading have no discernible impact on the long-term deformation of the TCFST.