Abstract: Unconventional shale oil and gas exploration and development are marked by novel characteristics like unconventionality,great depth,and extraction difficulties,coupled with highly intricate reservoir environments and rock structures. To pinpoint favorable temperature points and mechanical properties during reservoir exploration and development,this study chose organic-rich shale samples from the Niutitan Formation. Employing techniques such as nanoindentation,atomic force microscopy(AFM),and scanning electron microscopy(SEM),a comprehensive investigation was carried out on the micro-mechanical properties of shale oil reservoirs under different temperature conditions(25 ℃,300 ℃,400 ℃,and 500 ℃). The results show that the elastic modulus and hardness of brittle minerals(hard components) are substantially higher than those of the clay matrix(soft components). Moreover,the indentation depths of hard components are deeper. At a high temperature of 400 ℃,there is a distinct increase in indentation depth. As the temperature ascends from 300 ℃ to 500 ℃,the overall mechanical properties of shale exhibit a V-shaped tendency. After being subjected to high temperatures at 400 ℃,an enhanced visibility of pores is witnessed,along with a substantial increase in micro-cracks. This gives rise to shear and tensile fractures under stress,accompanied by a significant decline in elastic modulus and hardness. The correlation among various parameters is robust,with fitting values nearing 1,suggesting that temperature-induced alterations in the microstructure of shale are the main reason for the variations in its mechanical properties. This research offers vital micro-mechanical perspectives for the exploration and development of unconventional shale oil and gas,deepening our comprehension of how high-temperature conditions impact reservoir performance.