Abstract: In order to explore the influence of the geotextile filter layer on the flow rate of the perforated pipe, indoor experiments were combined with theoretical analysis. 5 kinds of staple fiber needle-punched nonwoven geotextiles with 4 kinds of areal density and 4 kinds of layers were set up for a total of 20 sets of tests. The flow rate of porous manifolds under different working conditions was observed and recorded. Through the dimensional analysis of the relational function formula of the geotextile filter layer to the flow rate of the porous manifold, regression analysis was performed to obtain the relationship expression between the parameters of the geotextile filter layer and the flow rate of the porous ma-nifold, and the calculated sink flow has a small error and high accuracy with the test value, which can be used to guide the actual project. When the parameters of the porous pipe were fixed, the confluence of the porous pipe under the geotextile filter layer was related to the surface density and the number of layers of the geotextile. The analysis of the test data shows that when the geotextile filter layer density is constant, the water volume of the porous manifold decreases with the increase of the number of geotextile layers, and the rate decreases. When the number of geotextile layers is constant, the water volume of the porous manifold decreases with the surface density increases. Hence, a reasonable selection of the surface density and number of layers of geotextiles in actual engineering can achieve better technical and economic effects.