The influence of SiO_2 on bonding phase fluidity was studied by measuring the projected area of tablets prepared using mixtures of fine iron ore and chemical reagents after sintering. The microstructure of samples was observed by optical microscope and SEM. Moreover,the relationship between SiO_2 and bonding phase fluidity and microstructure was analyzed by CaO-Fe_2O_3-SiO_2 system 1 300 ℃ isothermal section diagram. The main experimental conditions are as follows: in the composition of the bonding phase,CaO is 10%,15%,and 20%;SiO_2 is 2% and 6%; sintering temperature is 1 250,1 300 and 1 350 ℃; the sample cooling rate is quick. The results of the study showthat:(1) The fluidity of the binding phase decreases with the increase of SiO_2 content.Moreover,fluidity increases as the sintering temperature increases; however,when the CaO content is 10%( relatively lowproportion),the lifting temperature has limited effect on fluidity improvement.(2) The hematite proportion of the microstructure increases as the SiO_2 content increases.(3) When SiO_2 content increases,the solid phase ratio in the bonding phase grows,while the liquid phase ratio diminishes. Moreover the extension of the SiO_2 content in the liquid phase is larger than that in the solid phase. The influence of SiO 2 on bonding phase fluid was studied by measuring the projected area of ​​tablets prepared using mixtures of fine iron ore and chemical reagents after sintering. The microstructure of samples was observed by optical microscope and SEM. Moreover, the relationship between SiO 2 and bonding The main experimental conditions are as follows: in the composition of the bonding phase, CaO is 10%, 15%, and 20%; SiO 2 is The results of the study show that: (1) The fluidity of the binding phase decreases with the increase of SiO 2 content. However, when the CaO content is 10% (relatively low proportion), the lifting temperature has limited effect on fluidity improvement. (2) The hematite proportion of the microstru (3) When SiO 2 content increases, the solid phase ratio in the bonding phase grows, while the liquid phase ratio diminishes. Moreover the extension of the SiO 2 content in the liquid phase is larger than that in the solid phase.