In this study, R2O-Bi2O3-B2O3-SiO2 lead-free low-melting point glass was prepared by high temperature melting method and applied to automobile glass enamel. The effect of composition on the structure, thermal properties and acid resistance of glass was studied. The results show that with the increase of Bi2O3/B2O3 and Bi2O3/SiO2, the ［BO3］ and ［BiO3］ triangular structural units gradually decrease, the ［SiO4］ and ［BO4］ tetrahedral structural units gradually increase, and the network structure of glass is enhanced. When the alkali metal oxide content is 15% (mole fraction), the thermal expansion coefficient α25~320 ℃, transition temperature Tg and softening temperature Tf of double alkali glass are smaller than those of single alkali glass, and the acid mass loss rate Dr is lower. When n(Li2O)∶n(Na2O) is 1∶1, the α25~320 ℃ of double alkali glass is 9.35×10-6 ℃-1, the Tg value is reduced to 439.8 ℃, the Tf value is 481.7 ℃, and the Dr value is 0.006 70 g/cm2. Applying it to automotive glass enamel, the sintered enamel has good adhesion, blackness, coverage and gloss.