The vitreous and liquid phase of B2O3 are investigated by the temperature-dependent 11B CW-NMR technique. The results show that there are two processes in the structure changes of B2O3 glass with temperature increasing. Above 430℃, an increasing number of bonds begin to snap off and the number of boroxol rings is reduced accordingly. Above 600℃, a chain-like structure is formed, which is composed of B2O3 bipyramids. Above 930℃, this chain-like structure is broken to give B2O3 molecules.