Abstract: Using crystalline polycaprolactone diols (PCL), 4, 4′-diphenylmethane diisocyanate (MDI), N-methyldiethanolamine (MDEA) as main raw materials, a new type of temperature- and pH-sensitive polyurethane (PU) membranes were prepared from a two-step solution polymerization and a wet phase inversion method. The structure and properties were characterized by FT-IR, DSC, SEM, water contact angle tester, mechanical tester, and measurements of porosity and water flux. Results showed that the MDEA was successfully embedded into the PU macromolecules. All four PU membranes had a similar crystalline melting transition in their soft segments. The section of PU membrane was composed of skin layer, finger-like pores layer and sponge-like structure layer. With the increasing of —N(CH3)— group content, the porosity of PU membranes was increased, but the water contact angle and mechanical property of PU membranes were decreased. When temperature varied near the crystalline melting transition tempera-ture, their water fluxes changed markedly, showing the temperature sensitivity. When the pH changed from 8.5 to 10, their water fluxes were also obviously changed, showing the pH sensitivity.