The density of states and band structures of α-V

2

O

5

and Li-intercalated V

2

O

5

(Li

x

V

2

O

5

x=0.5 and 1.0) have been studied using a first-principles calculation based on density function theory with the local density approximation. The results indicate that V

2

O

5

is an indirect-gap semiconductor; the intercalation of Li will not change its way of electron transition. While

the intercalation of Li lowers the energy of conduction band

and then narrows the band gap. At the same time

due to the intercalation of Li

the split-off in the conduction band of V

2

O

5

disappears because of the split of conduction band. The Fermi level of Li

x

V

2

O

5

increases dramatically due to the electron transfer from Li2s to the V

2

O

5

host

which is probably the main reason why the optical band-gap augments with the Li intercalation.