The challenge of farming in mountainous areas is soil conservation to avoid erosion. A method to control soil erosion is mulch technology. Mulch can reduce rain energy, preventing damaging the stability of the soil structure. Mulch that is widely used is plastic mulch, but it has several disadvantages. Thus, bio-geotextile is a mulch alternative. Biogeotextiles can be made from mending, a type of grass belonging to the Cyperaceae family and is originally from Southeast Asia. This study aims to determine the effect of the number of layers and weaving spacing of bio-geotextile in controlling soil erosion and the best treatment of Mendong bio-geotextile in controlling soil erosion. The method used was a Factorial Randomized Block Design (RBD), which consists of two factors, the number of layers (1 -3 layers) and weaving spacing (0.5-2 cm. It is found that Mendong bio-geotextile with 1 layer and 0.5 cm weaving spacing was the best and most effective treatment in controlling soil erosion. The Mendong bio-geotextile has proven to be effective in reducing soil loss due to erosion. Compared to the soil without bio-geotextile treatment, Mendong's bio-geotextile best treatment can reduce the amount of soil loss up to 98.6%.