In view of the special working conditions of 350 ℃ high temperature， 17 MPa high pressure and multiple cycles of steam huff and puff in thermal production wells， the mechanical properties of TP110H during the first steam injection and multiple cycles of injection and production are studied. The test shows that TP110H generates thermal stress up to 764 MPa during thermal injection， and the material generates a small amount of plastic strain and stress relaxation effect. The string stress of 15 rounds of steam huff and puff is basically stable， and the strength and elongation at room temperature are basically unchanged before and after the experiment. The high-temperature yield strength at 350 ℃ decreases by about 50 MPa， the tensile strength decreases by about 13 MPa， and the elongation after fracture decreases by about 2%.