In order to investigate the percolation law of tight sandstone reservoirs in the western Sulige，combined qualitative and quantitative methods are applied to analyze pore structure through thin section and conventional mercury injection data. Based on gas-water relative permeability test and visualized real sandstone models，gas-water displacement and pressure relief experiments are further carried out to simulate the percolation law and fluid distribution of different pore types during the process of gas reservoir formation and development. According to the proportion of different pores，the pore assemblage types can be divided into four categories：dissolution pore-intergranular pore，intercrystalline pore-dissolution pore，dissolution pore-intercrystalline pore and intercrystalline pore. The pore-throat characteristics and percolation law of representative samples of four types of pores are analyzed. The results show that the percolation law of different pore types varies obviously，and the irreducible water saturation decreases gradually with the physical properties of reservoirs with various pore types becoming better and better. The relative permeability of gas phase at irreducible water saturation increases gradually，the width of the two-phase percolation area increases continuously and the percolation ability is enhanced. The interaction between gas and water is reduced gradually. The visual gas-water displacement type gradually changes from finger displacement to homogeneous displacement with larger displacement degree with the improvement of pore type，which is beneficial to the formation of effective reservoirs filled with natural gas under the same hydrocarbon generation conditions. The pressure relief experiment shows that the time required for pressure relief of samples with pore type is short，the degree of pressure drop increases，and the recovery is higher. The residual water in samples with poor pore type increases，which decreases the relative permeability of gas phase and recovery. According to mercury injection and relative permeability test，the production pressure difference of the nodal point from the irreducible water to removable water in the formation is 7 MPa，which provides a theoretical basis for reducing the risk of producing water and enhancing gas recovery in the western Sulige.