<p>Providing a practical TiO₂-constrained guideline for vanadium titanomagnetite (VTM) sintering not only contributes to reducing CO₂ emissions in sintering process, but also promotes the cleaner blast furnace smelting process with high pellet ratio. However, the threshold TiO₂ level for high-titanium and low-silicon VTM sintering remains unclear currently. In this paper, the effect of TiO₂ content on the sintering performance of VTM and the metallurgical properties of VTM sinter were systematically investigated through sinter pot tests. A comprehensive evaluation index for VTM sinter was proposed. The action mechanism of TiO₂ was elucidated by analyses of theoretical thermodynamics, a liquid-phase mechanism model, and sinter consolidation characteristics. The results indicate that increasing TiO₂ content inhibits the formation of initial calcium ferrite and silico-ferrite of calcium and aluminum (SFCA), while promoting the formation of more high-melting perovskite (CaTiO₃) and increasing sinter porosity. The VTM sinter structure transforms from dense interwoven structure to a microporous thin-walled structure, especially when the TiO₂ content exceeds 4.0 wt%. Combined with sinter indices and metallurgical performance data, the comprehensive evaluation indices for VTM sinter across different methods sharply decreased at the TiO₂ range of 4.0 ~ 5.0 wt%. The threshold TiO₂ level for high-titanium and low-silicon VTM sintering is 4.0 wt%. When TiO₂ content does not exceed 4.0 wt%, sinter indices and metallurgical properties are generally superior, with tumble index, yield, productivity, reducibility index (RI) and reduction degradation index (RDI_+3.15) exceeding 69 wt%, 82.5 wt%, 1.55 t·m⁻²·h⁻¹, 80 wt% and 79 wt% and solid fuel rates below 66 kg·t⁻¹.</p> Graphical Abstract <p></p>