The effect of graft yield on both the thermo-responsive hydraulic permeability and the thermo-responsivediffusional permeability through porous membranes with plasma-grafted poly(N-isopropylacrylamide) (PNIPAM)gates was investigated. Both thermo-responsive flat membranes and core-shell microcapsule membranes with a widerange of graft yield of PNIPAM were prepared using a plasma-graft pore-filling polymerization method. The graftedPNIPAM was formed homogeneously throughout the entire thickness of both the flat polyethylene membranes andthe microcapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeability wereheavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulic permeability (waterflux) decreases rapidly at 25℃ because of the decrease of the pore size; however, the water flux at 40℃ increasesfirstly to a peak because of the increase of hydrophobicity of the pore surface, and then decreases and finally tends tozero because of the pore size becoming smaller and smaller. For the diffusional permeability, the temperature showsdifferent effects on the diffusional permeability coefficients of solutes across the membranes. When the graft yieldwas low, the diffusional coefficient of solute across the membrane was higher at temperature above the lower criticalsolution temperature (LCST) than that below the LCST; however, when the graft yield was high, the diffusionalcoefficient was lower at temperature above the LCST than that below the LCST. It is very important to choose ordesign a proper graft yield of PNIPAM for obtaining a desired thermo-responsive "on/of" hydraulic or diffusionalpermeability.