The α-Ga2O3 holds significant research value on high power device applications for its superior breakdown voltage performance. However, research concerning the doping of α-Ga2O3 remains scant, and the optimal dopant remains unidentified. To identify a potential n-type dopant, a theoretical study of the effects of group IV atoms (Si, Ge, Sn) on doped α-Ga2O3 was evaluated through the first principles calculations. We have systematically explored the lattice deformation, band structure, density of state, charge density difference and electron localization functions. The electron mobility is then evaluated by the deformation potential theory. The lowest formation energy of the Si-doped system suggests it forms the most readily. Meanwhile, Si loses approximately 1.5 times more electrons than Ge and Sn in the doped α-Ga2O3, as evidenced by the charge density difference and electron localization functions. Furthermore, our results reveal that Si is a superior dopant over Ge and Sn. It is owing to a small interaction between the Si 3s state and the Ga 4s generated host CBM, resulting in a minimal effect on the CBM even at high doping levels. The findings of this study have important consequences for improving the doping process of α-Ga2O3 and achieving the development of optoelectronic devices.