The testing and characterisation of high-temperature properties of materials are one of the current challenges in the development of high-temperature solid mechanics, and it is of great significance to carry out in-situ high-temperature mechanical experiments to study their micro-deformation as well as microstructural evolution. In this paper, a set of in situ high-temperature mechanical measurement systems is established based on optical micro-imaging, which can carry out in-situ tensile, fatigue and creep mechanical property measurements under atmospheric pressure or vacuum environments from room temperature to 1000 ℃. Firstly, uniaxial tensile and fatigue experiments were carried out using standard 7075 aluminum alloy to verify the loading stability of the measurement system. Second, in-situ high-temperature imaging experiments were carried out using a nickel-based single-crystal alloy, and analyses of the temperature characteristics of the heat source as well as the quality of the in situ high-temperature imaging were carried out. The results show that the measurement system can achieve stable loading of the test specimen and clear in-situ imaging of optical microscopy. Finally, in-situ uniaxial tensile and fatigue experiments of nickel-based single crystal alloys were completed at 900 ℃ with the help of the measurement system, and the crack initiation, propagation and microporous evolution were observed in real-time during the loading process, which provided an effective experimental platform to reveal the correlation mechanism between the macro-mechanical properties of high-temperature alloys and their microstructural evolution.