Based on 80V2O5-20P2O5-xSb2O3(x=0,1,3,5 mol%) system glass and heating 1 h at 850 ℃, a glass sample was successful prepared. The mechanism of the increased crystallization stability of Sb2O3-doped vanadium phosphate sealing glass was investigated with infrared absorption spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR) . The tests showed that, by introducing Sb2O3 into glass system, the amount of BO increased while NBO decreased, and part of the NBO structure broke and turned into BO structure. Meanwhile, with the increase of V4+/V5+, these two factors led to the breaking of V=O bond, which was essential for the formation of V2O5 crystalline phase and inhibited the formation of the crystalline phase. By introducing Sb2O3 into the glass system, the amount of (V2O8)n zigzag chain increased while (VO3)n single chain decreased. The intermediate structure of the network equilibrium was destroyed by the introduction of Sb2O3.The (VO3)n single chain was gradually transformed into (V2O8)n zigzag chain and the glass structure became tighter. It was difficult to crystalline. The crystallization stability of glass was improved.