Abstract: In order to reveal the quantitative relationship between the microscopic features of the Jurassic sandstone and the physical-mechanical properties in Burtai Mine, a rock uniaxial compressive test, thin slice polarization microscope experiment and acoustic velocity measurement experiment were applied to study the micro structure of the rock sample, the macro-mechanics property and acoustic velocity. A mathematical statistics method was applied to quantitatively analyze the average particle size and particle selectivity of the Jurassic sandstone affected to the macro-mechanical properties and acoustic velocity. The results showed that the micro structure features of the sedimentary rock in Buertai Mine affected to the macro mechanics properties of the rock. The average partical size of the clastic partical was reduced and the sorting degree was good, thus the rock compaction was increased, the porosity was decreased and the rock mechanical property was enhanced. The features were different to the Carboniferous Permian coal measural sandstone. The mechanics strength of the coal measure sandstone would have an increased tendency with the partical size increased. The average partical size of the rock samples and the sorting would be affected to the acoustic velocity. When average partical size of the rock samples was reduced, the selectivity of the clastic particles would be better, the compaction would be higher and the acoustic velocity of the rock sample would be higher.