With the enhancement of exploration extent, deep oil—gas exploration is inevitable . It's imperative to figure out the law of porosity evolution of deep reservoirs as well as to raise forecast accuracy,which is the basis of deep exploration . Through systematic collection of cuttings and core samples from Well kun 2, Qaidam Basin and using casting thin sections, scanning electron microscope and logging data interpretion, the characters of petrology, mineralogy and physical properties of reservoirs in both Paleogene and Neogene stratums are systematically analysed .As a result, the content of argillaceous matrix and the porosity evolution of sandstones are closely related . In order to complete the forward modeling of the process of porosity evolution, well sorted aeolian quartz sands and the fine grained red clay are chosen as materials, and four kinds of quartz sands are made respectively containing clay matrix of 5%, 10%, 15%, 20% to carry out the simulation . Unconsolidated sediments compaction simulation was carried out from 1.4 MPa to 210.4 MPa, containing 21 cycle experiments respectively . The results of stimulant experiment against the core data of Well kun 2 under a comparative analysis shows that the much higher the content of argillaceous matrix in clastic rocks was, the smaller the primary porosity would be and the faster the porosity would decay ; for arenite with low argillaceous content, when the overburden pressure reached 76.5MPa, a large number of particles were broken and rearranged, which led to intergranular volume reduction and occurrence of few linear intragranular fractures,meanwhile the reservoir physical properties significantly worsen . The experimental data of compaction simulation can provide a basis for the reservoirs quality prediction of the sandstones in rapid subsidence area .