Abstract: Horizontal drainage pipe and radial well are the typical drainage systems for tailings reservoir.The geotextile is the main filter material for drainage pipe (radial tube)，but its filter layer lacks of strict filter design，and its filtration performance is quite different.Through describing the typical filter structure and the effect of each part on the filter performance，the existing filter criteria and the filter test techniques，and the progress on durability of filter layer，research progresses on the tailings statistical characteristics，the geotextile parameters，filtering process of geotextile filter layer are summarized，and several research directions in filter design of the tailings dam drainage system are pointed out，including researchs on impacting of physical and mechanical properties of tailing on geotextile filter layer, characterization methodology of geotextile, measurement of geotextile characteristic parameters, long-term filtration test methodology and equipment, and numerical method for filtration process of geotextile filter,which provides references for the filter design of the tailings dam drainage system.

Key words: Tailing dams, Geotextile, Drainage system, Filter design, Filter criterion