Abstract: The Ti-doped diamond-like carbon (Ti-DLC) film was prepared by multi-target magnetron sputtering technique, and was heat-treated at different temperatures (300,350,400 ℃). The effects of heat treatment temperature on the microstructure, composition, band structure and field emission properties of the film were studied. The results show that compared with those before heat treatment, the proportion of sp²-C clusters in the Ti-DLC film after heat treatment at 300 ℃ increased; the optical band gap was the smallest, and the turn-on field with value of 5.43 V·μm^-1 was the smallest, indicating the film had the best field emission performance. As the temperature was higher than 300 ℃, the content of diamond-like carbon in the films dropped, and a large amount of TiO₂ formed; the optical band gap and the turn-on field increased, indicating the field emission performance of the films got worse. The field emission current of the film was not affected by the heat treatment temperature.