Objective To study the mechanical properties of L80 steel in CO2 / H2S environment. Methods Slow strain rate tensile testing machine was used to conduct tensile tests on L80 samples in specific corrosion conditions, and the influence rules of each factor on the mechanical properties of L80 steel were analyzed. Results In CO2/H2S environment, with the increase of water cut, the tensile curve of L80 tubing steel appeared to degrade, the yield strength, tensile strength, and elongation all decreased; With the increase of tensile stress, the yield strength of L80 steel had no significant change, the tensile strength and elongation decreased, and the corrosion rate significantly changed when the tensile stress exceeded 0.8σs, which showed strong stress corrosion sensitivity; With the increase of H2S partial pressure, the mechanical properties of L80 steel decreased, showing relatively strong hydrogen embrittlement sensitivity, but influence of CO2 partial pressure on L80 steel was not obvious; Tensile curve of L80 steel underwent mild degradation with the increase of temperature, the elongation and yield zone width reduced with a small amplitude, but the tensile strength just changed a little. Conclusion Temperature and CO2 had a small effect on the mechanical properties of L80 steel; The increase of water cut and tensile stress reduced the mechanical toughness of L80 steel, accelerated the corrosion rate of L80 steel, and shortened the anticorrosion longevity of L80 steel; Mechanical properties of L80 steel were more sensitive to H2S than CO2, and sample fracture was the result of the combination of machine tensile and stress corrosion.