Abstract: An oil shale in situ pyrolysis simulation experiment with different heating rates, heating time and water contents was carried out to assess the influences of these parameters on the physical properties of oil shale in situ conversion production. The physical properties of oil shale in situ conversion production were analyzed using nuclear magnetic resonance T₂ spectra. The results showed that the slow heating rate (the increase of reaction time) was beneficial to the development of organic micro-pores, while the increase of heating rate was beneficial to the development of micro-cracks. With the increase of constant temperature time, the physical properties of oil shale can be improved, and small pores gradually develop into relatively larger pores. High-temperature water may be used as a catalyst, reactant and solvent to participate in the reaction. On the one hand, it is beneficial to react with organic matter to generate organic pores; on the other hand, high-temperature water may react with oil shale minerals, thus improving the physical properties of oil shale.