The Sulige gasfield is on the whole regarded as a tight sandstone field based on the permeability of reservoirs under overbur- den. There exists a linear relation between the permeability with a relative variation range to the 1/3 power and the normal one to the 1 / 2 power under 50~60 MPa. The porosity of reservoirs is sensitive to overburden stress to some extent and a fairly good linear rela- tion is also found between the 1/3 power of the overhurden porosity/normal porosity ratio and the normal porosity. Data of the SEM and mercury-injection experiment indicate that the pore radius shows a continuum distribution from the hundred-micrometer scale to the nanometer one. The lower the permeability of reservoirs, the less proportion the micron-pore has and the more pore space the nano-pore takes. Most throat radius is less than 1μm, representing a nanometer-scale continuum distribution. There exists a nega tire correlation between the irreducible water saturation and normal permeability. The irreducible water saturation corresponding to a given permeability is not a definite value but a value range. The fitted relation shows that there is a power function relation between the normal porosity and the reserve coefficient per unit thickness. Because of the higher porosity sensibility to overburden stress and the lower gas saturation, reservoirs with lower porosity contain less natural gas re~n,,r~o~ *h~n tb,,, ;d. 1.;-~. :...