In this study, the novel supported liquid membranes were prepared by incorporating room-temperature ionic liquids into poly(vinylidene fluoride)(PVDF) matrix via phase separation technique. The new technique which enables to prepare the novel supported liquid membranes consisted mainly of two processes; the low temperature phase separation and the high temperature quenching process. The membranes had excellent stability under sever operating conditions. Also the permeation behaviors of acid gases (H2S, CO2) and CH4 through the membranes were investigated for verifying usefulness of the membranes to remove acid gases from crude natural gas. The novel supported liquid membranes exhibited very high H2S, CO2 permeability coefficients and H2S/CH4, CO2/CH4 selectivities, respectively.