Abstract: CF₃SO₂F is a new environmentally friendly insulating gas with a potential to replace insulating gas SF₆. Considering the biological toxicity of CF₃SO₂F, it is of great engineering importance to develop a highly sensitive sensor for leak detection. Based on the first-principles calculation, this paper analyzes the gas sensing response characteristics of β-Ga₂O₃ (010) surface in the presence and absence of oxygen vacancy as a gas sensing material to CF₃SO₂F. The work function of the pristine β-Ga₂O₃ (010) surface system is changed significantly with and without CF₃SO₂F adsorption, and the recovery time at room temperature is short. Moreover, the presence of environmental molecules O₂ and CO₂ does not affect the selective detection of CF₃SO₂F on the pristine β-Ga₂O₃ (010) surface. Therefore, the pristine β-Ga₂O₃ (010) surface can be used as a potential field-effect transistor type gas sensing device material for CF₃SO₂F with high stability, good selectivity, high sensitivity, and reusability. The introduction of oxygen vacancy defect makes the β-Ga₂O₃ (010) surface adsorption system unable to provide effective selectivity to detect CF₃SO₂F in the presence of environmental molecular O₂ and CO₂. Therefore, oxygen vacancy defects should be avoided as much as possible during the synthesis of β-Ga₂O₃ (010) surface materials. This paper proves that pristine β-Ga₂O₃ (010) surface can be used as a potential CF₃SO₂F field-effect transistor gas sensor in theory, which can guide the subsequent experimental preparation of gas sensors.