Abstract: A multifunctional permeability test apparatus is developed to investigate the permeability and filtration properties of geotextiles under tension as encountered in practice. By adopting two individual sets of stable and reliable counterweight-and-lever loading assemblies, permeability tests can be carried out for geotextiles under either uni-axial or biaxial tension with different tensile stresses. A multifunctional permeameter is designed and developed for performing constant head and falling head permeability tests on geotextiles or soil-covered geotextiles with and without vertical load. The preliminary experimental results show that the permeability of geotextiles without tension and vertical load obtained from the newly developed apparatus is generally consistent with that obtained from a permeameter conform to the national and international standards. Moreover, all functions designed for this apparatus can be accomplished. This provides a basis for future studies on the permeability and filtration properties of geotextiles under tension.