Abstract: The interfacial heat transfer coefficient of cast iron is an important parameter to reflect the heat transfer degree between the frozen sand cast iron alloy and cast iron alloy, which is of great significance for the analysis of microstructure properties of cast iron alloy. In this study, the change rule of the interfacial contact temperature of the alloy with time was measured. Based on this, the characteristics of the interfacial heat transfer were analyzed, and the function of the interfacial heat transfer coefficient changing with the initial interfacial temperature was obtained.Meanwhile, the as-cast microstructure and mechanical properties of the castings solidified in the frozen sand mold were analyzed. The results show that the interfacial heat transfer coefficient decreases with the increase of the initial temperature of the frozen sand mold, and increases with the decrease of water content. At the initial freezing temperature of-35℃,-30℃ and-25℃ with moisture content of 6wt.%, the peaks of interface heat transfer coefficients of cast castes are 195663W/（m~2·K）, 147933W/（m~2·K） and 120836W/（m~2·K）. At the initial freezing temperature of-35℃,-30℃ and-25℃ with moisture content of 5wt.%,the peaks of interface heat transfer coefficients of cast castes are 209257W/（m~2·K）, 176878W/（m~2·K） and 134472W/（m~2·K）. Under the same moisture content, the lower the initial freezing temperature, the finer the pearlite grain, the higher the graphitization degree and the higher the tensile strength.