Abstract: Tuyere sampling was conducted in a COREX melter gasifier during down time. Through the detection analysis of tuyere samples, the effect of gas phase on the liquid permeability of the stock column was expressed by the reciprocal of pressure difference degree, while the effect of liquid phase on the liquid permeability was expressed by the product of voidage and temperature intensity. Based on those, a formula was established to characterize the liquid permeability of the stock column. Investigations on 2 batches of tuyere samples show that there is a compatible corresponding relation between the liquid permeability index and residue iron of tuyere samples at different positions in the melter gasifier. Moreover, some influencing factors of the liquid permeability index were analyzed. it is found that residual acid gangue can directly fall into the hearth in unsteady furnace conditions, which leads to the slag melting temperature in a certain position over 1500℃ and thus affects the fluidity of iron slag. Several technical measures are proposed, such as increasing material layer thickness, adopting a proper slagging regime, and controlling uniform gas flow distribution, to provide helps to improve the liquid permeability of the stock column in the melter gasifier.