In this work, physical properties such as dynamic viscosity at （298.15 to 338.15） K, surface tension, andrefractive index at temperatures （303.15 to 333.15） K of pure ａnd aqueous Nmethyldiethanolamine （MDEA） solutions （with mass fraction of MDEA of 0.3228 ａnd 0.4880） were measured at atmospheric pressure ａnd correlated. A thermogravimetric analyzer （TGA） was used to study the thermal stability of solvents in the presence of nitrogen （20 mL· min-1）, at a heating rate of 10 °C· min-1.