Various materials such as water, oil heat, ionic liquids and also molten salt are selected to serve as heat transfer fluid. The nitrate based molten salt that has been use in this study consists of binary, ternary and quaternary salt mixture with different weight composition. DTA, TGA and DSC were performed to obtained melting point, thermal stability and heat capacity. The melting point for ternary and quaternary mixtures are closely 100 ºC compared than binary mixture. Quaternary mixture shown the highest result in thermal stability and heat capacity with the value 701 ºC and 4.7 J/g ºC  and have fulfilled the targeted characteristic as heat transfer fluid