In-situ conversion technology has become a critical method for exploiting medium-low maturity shale reservoirs. Thermal stimulation leads to the conversion of kerogen and heavy hydrocarbons into valuable pyrolysis oil and gas. This is a thermal-fluid-solid multi-field coupling process, along with the expansion of pre-existing fractures and generation of new ones, resulting in changes in the pore structure and mechanical properties, which greatly affect the seepage of thermal fluids and release of pyrolysis oil and gas. In this paper, in-situ conversion experiments under different pyrolysis final temperatures were conducted on medium-low maturity shale samples from the Chang 73 section of the Ordos Basin. The pore structure of shale samples treated at different temperatures was quantitatively characterized by nitrogen adsorption method. The uniaxial compression tests were employed to mechanical properties. The results indicate that medium-low maturity shale predominantly consists of mesopores, which contribute an average of 70.81% of pore volume. As heat treatment temperature increases, pore structure becomes more complex. Especially at 450 ℃, the primary contributor of the large increases in pore volume and surface area is a rise in the quantity of mesopores and micropores. Shale Young's modulus and compressive strength reveal a slight rise and then a noticeable decrease as heat treatment temperature rises. This work illustrates how mechanical characteristics and pore structure of medium-low maturity shale react to pyrolysis temperature, offering fundamental data for in-situ conversion multi-field coupled simulation.