Abstract: Sinter ore is one of the main materials of blast furnaces in China, and the productivity of the blast furnace and the economic and technical indicators of the ironmaking process are directly influenced by sinter yield and quality. Therefore, the ore-blending process should be optimized based on the high-temperature characteristics of iron ore to improve the sinter yield and quality and the energy efficiency of the ironmaking process. The liquid phase fluidity of iron ore is a vital characteristic of high-temperature sintering, since a suitable liquid phase fluidity of blended ores produces a sintered body with a stronger bonding strength. In this paper, by simulating the contact state of the iron ore particles and the calcareous flux particles in the actual sintering adhering fines, the FactSage thermodynamic calculation and the visible micro-sintering tests were conducted to study the liquid phase fluidity indexes of different iron ores and the major melt formation characteristic factors that influenced the liquid phase fluidity of iron ore under fixed CaO ratio conditions. The results show that the rule of liquid phase fluidity of iron ores under a fixed CaO ratio is different from the rule of liquid phase fluidity of iron ores with fixed alkalinity. According to the fitting relationship between the calculation results by Factsage software and the testing results of liquid phase fluidity index of the 9 kinds of iron ores, the formed melt content of iron ore is the most important melt formation characteristic factor that affects liquid phase fluidity. The formed melt content and the liquid phase fluidity index are directly related, and the coordination mechanism of liquid phase fluidity of iron ore is based on the principle of linear superposition of the formed melt content. Furthermore, the content of gangue minerals affects the liquid phase fluidity of iron ore to some extent. The liquid fluidity index decreases greatly with increased SiO₂ content, leading to lower formed melt content, while the liquid fluidity index slightly increases with increased Al₂O₃ content.