In the present paper, SiO2 glass ceramic and Ti–6Al–4V alloy were successfully brazed with Ag–21Cu–4·5Ti active braze alloy. The interfacial microstructure and evolution course of SiO2 glass ceramic/Ti–6Al–4V joint were studied in detail. According to the experimental results, active element Ti plays a quite important role in the formation of reaction layers on the joint interface. The reaction products of the joint are TiSi2, Ti4O7, TiCu, Cu2Ti4O and Ti2Cu respectively. The interface evolution can be generally described by four stages, which are solution and diffusion of atoms, reaction among atoms, formation of reaction layers and precipitation of solid solution layers respectively.