Abstract: Objective Under extreme ambient temperatures, issues such as excessive temperature rise and intensified contact force fluctuation readily occur in the PC（pantograph-catenary） contact zone. Therefore, it is necessary to reveal the thermo-mechanical coupling effects of the PC system under varying ambient temperatures and investigate the evolution law of temperature and stress. Method Based on dynamics and thermodynamics theories, a thermo-mechanical coupling model of the PC system considering multi-physical field influences（thermal, dynamics, and electrical） is established. The impact of ambient temperature on the thermo-mechanical coupling characteristics of the PC system is investigated. Result ＆ Conclusion The steady-state temperature of carbon strip shows a positive correlation with ambient temperature, while its total temperature rise and steady-state stress exhibit negative correlations with ambient temperature. For every 20 ℃ increase in ambient temperature: the steady-state temperature of carbon strip increases by 12.6 ℃, the temperature rise decreases by 7.4 ℃, and; the steady-state stress decreases by 0.755 MPa. At ambient temperatures of-60℃ and 90℃, the total temperature rise reaches 249.46 ℃ and 183.46 ℃, respectively. Even under low ambient temperature conditions, the surface temperature of carbon strip can rapidly rises to a level that may cause severe wear.