The conductivity of W-doped β-Ga2O3 is investigated by using the ultra-soft pseudopotential (USP) approach of the plane-wave based upon density functional theory. The optimized structural parameters, total electron density of states, and energy band structures of β-Ga2(1-x)W2xO3 (x=0, 0.0625, 0.125) are calculated. It is found that the volumes are slightly increased and the total energies are going up in the Ga2(1-x)W2xO3 system with increasing W-doping concentration, which causes the system instability. When the W concentration is smaller, the calculated conductivity and electronic mobility are higher, but when the W concentration is increased, the average electron effective mass becomes bigger and the energy gap becomes narrower. The results are consistent with experimental data.