Abstract: To improve the production and quality indices of laterite ore sinter, the effect of MgO/Al₂O₃ mass ratio on the liquid volume and viscosity during high-temperature sintering was investigated, based on thermodynamic analysis. The influence of MgO/Al₂O₃ ratio on the phase composition and bonding phase strength of sinter was discussed through micro-sintering test, and the impact of MgO/Al₂O₃ mass ratio on sintering mineralization behavior of limonitic laterite ore was clarified. Finally, the validity of our findings was confirmed through sinter-pot large-scale sintering test. The results of micro-sintering test showed that the bond phase was mainly composed of calc-magnesia melilite and olivine and their compressive strength exceeded 4 000 N/P, under the condition of m(MgO)/m(Al₂O₃)=0.5~0.8, sintering temperature of 1 300 ℃, sintering atmosphere of 5%CO+95%N₂, binary basicity of m(CaO)/m(SiO₂)=1.3. The sinter-pot verification test revealed that increasing the MgO/Al₂O₃ mass ratio from 0.5 to 0.7, the yield of sinter did not change significantly and remained at approximately 70%, but its tumbling strength of sinter increased from 49.73% to 56.67%, and the optimal MgO/Al₂O₃ mass ratio was in the range of 0.6-0.7.