As a star of the MXene materials, 2D titanium carbide (Ti₃C₂T_x) has attracted broad interest from worldwide researchers in view of its potential application in energy storage, chemical sensing, electromagnetic interference shielding and flexible electronics. In order to further improve performances and satisfy the needs of emerging flexible applications, there is an urgent need to increase the electronic conductivity, environmental stability and flexibility of Ti₃C₂T_x film. Herein, a two-stage thermal treatment process in an argon atmosphere at low temperature (300 °C) is proposed to address this challenge. The resulting Ti₃C₂T_x film shows a 16-fold increase in electronic conductivity, while its environmental stability and flexibility are also greatly enhanced. Furthermore, systematic investigation into the microstructure and variations of Ti₃C₂T_x films before and after thermal treatment shed light on the underlying mechanism, which contributes to a deeper understanding of MXene properties and offers general guidance for improving the performance of MXene films.