  A new layered compound LaOTlF2 is designed and investigated using
first-principles calculations in this work. The parent compound is an insulator
with an indirect band gap of 2.65 eV. Electron-doping of the parent compound
makes the material metallic. In the meantime, several lattice vibrational modes
couple strongly to the conduction band, leading to a large electron-phonon
coupling constant and conventional superconductivity. The highest
superconducting transition temperature Tc is predicted to be approximately 8.6
K with {\lambda} about 1.25 in the optimally doped LaO0.95F0.05TlF2, where
{\lambda} is calculated using the Wannier interpolation technique.
