Kerosene(Jet A-1), one of the propellants for each stage's engine of the Korea Space Launch Vehicle-Ⅱ(KSLV-Ⅱ), functions as coolant at the same time as it flows inside the cooling jacket of the combustion chambers and is injected through the film cooling holes.A physical surrogate mixture model to reproduce the thermophysical characteristics of Jet A-1 has been selected and the thermodynamic/transport properties of the model fuel under high pressure including supercritical conditions have been estimated using SUPERTRAPP(NIST SRD4). Comparisons with the measured properties suggest that proposed database can be used to extract properties of Jet A-1 for conjugate heat transfer analysis of liquid propellant rocket engine thrust chambers. Predicted combustion/cooling performance of regeneratively cooled thrust chambers shall be validated through comparisons with upcoming firing test results.