It is always the key point in the field of oilfield development to study the oil circulation condition and percolation law in reservoirs.Based on the percolation theory,a three⁃dimensional percolation model is established by numerical simulation method,which can simulate the distribution of cracked joints,percolation laws,percolation thresholds of reservoir rocks and determine whether they are permeable.The results show that when the connectivity probability increases from 0,the total number of clusters increases.When the connectivity probability increases to 0.17,the total number of clusters begins to decreases.When the connectivity probability is small,the percolation probability increases slowly with the increase of the connectivity probability.When the connectivity probability exceeds the first critical value,the growth rate of the percolation probability suddenly increases.When the connectivity probability exceeds the second critical value,the percolation probability begins to slowly increase again and eventually approaches 1.The seepage cluster can accurately determine whether the porous medium is permeable and accurately capture the percolation threshold.The size of the percolation threshold is related to the size and shape of the medium.There is no obvious regularity between the maximum cluster size and the average cluster size,the maximum cluster size and the total number of clusters.It is concluded that this three⁃dimensional percolation model can simulate the long⁃range coupling mutation caused by the change of connectivity probability in porous media,which can be used to simulate the permeability and percolation law of rock.