Abstract: The tensile properties of 110H steel for the casing as used in a certain thermal recovery well are tested at different temperatures.The test temperatures are selected from those as recommended under applicable specification i.e., 180, 240, 290, 325, 350 ℃, and the room-temperature tensile test is added.The test results show that along with the increase of the temperature, both the yield strength and the tensile strength of the said steel decrease, and the yield strength becomes more sensitive to the temperature.The decrease degree meets the requirement as specified under the applicable specification.Likely the elastic modulus also decreases with increasing of the temperature.The results of the above mentioned tests are fitted, and the fitting reliability is rather high, which is worth referring for design and selection of the casing string.