With the rise of passivated emitter and rear cell double-sided glass components industries，the need for photovoltaic ink for photovoltaic glass backsheet is growing annually. After the photovoltaic ink is prepared for the coating, the degree of its density will have a direct impact on the reflectivity of photovoltaic ink coating and conversion efficiency ulteriorly of photovoltaic cell. By changing the n(Bi2O3)/n(SiO2), the crystallization of glass flux and its effect on the photovoltaic ink prepared by Bi2O3-B2O3-SiO2 glass flux were investigated. The different characteristics of glass flux were analyzed by using DSC and Raman. The microstructure and reflectance of various photovoltaic ink coating were studied by using XRD and SEM, and the mechanism for the enhancement of light reflection was proposed. The results show that the increase of n(Bi2O3)/n(SiO2) leads to an increase in ［BiO3］ and ［BiO6］ ionic groups. Thus, the destruction ability of the ［SiO4］ glass network is enhanced, and the transition temperature and crystallization peak temperature of glass flux gradually decrease. The crystallization ability of glass flux gradually increases. A large number of flaky Bi2SiO5 crystals are gradually precipitated from photovoltaic ink coating in a short period of time. After preparing them as photovoltaic ink coating, the reflectivity of the coating gradually increases with the elevation of n(Bi2O3)/n(SiO2). With n(Bi2O3)/n(SiO2) of 30∶60, the reflectance of photovoltaic ink coating can be enhanced to 82.66% in the near-infrared wavelength range. This is mainly due to the fact that the pores and cavities in photovoltaic ink coating act as heterogeneous interfaces, prompting the precipitation of Bi2SiO5 crystals and filling them into the pores and cavities of photovoltaic ink coating, resulting in an increase in the densification of photovoltaic ink coating and thus an enhancement of the reflective ability of photovoltaic ink coating to light.