The characteristics of the reinforced soil interface form the foundation for designing reinforced structures. The method of stitching transverse rib geotextile reinforcement is an innovative technology that enhances traditional geotextiles. Three-dimensional reinforcement is employed to enhance interaction at the reinforced soil interface and fully exploit the high strength advantages of geotextiles. To investigate the influence of the number and height of transverse ribs on these characteristics, a discrete element numerical simulation was conducted based on indoor test results, enabling analysis of mechanical responses at different numbers and heights of transverse ribs from macroscopic and microscopic perspectives. The results show that the shear strength of the reinforced soil interface can be significantly improved by stitching the transverse rib geotextile. The shear stress-displacement curve is mainly divided into two parts : linear growth stage and stable stage. With the increase of the number and height of the transverse ribs, the overall shear strength of the geotextile increases. When the ratio of the height of the transverse ribs to the thickness of the soil layer is 0.5, the shear strength of the interface is significantly improved and the strain value on each transverse rib is more uniform. Therefore, it is recommended that the height of the transverse ribs is 0.5 times the reinforcement spacing in practical application. With the increase of the number of transverse ribs, the quasi-cohesive force increases obviously and the quasi-friction angle changes little. With the increase of the height of transverse ribs, the quasi-friction angle increases obviously and the quasi-cohesive force changes little. In the process of direct shear test, the strain of the paving part of the geotextile and the strain on the transverse rib increase with the increase of the number and height of the transverse ribs. The maximum strain is at the joint of the two. The strain of the first transverse rib is the largest and the fastest increase, which makes the joint of the transverse rib become the key of the whole system. Therefore, in practical application, the height, setting position and stitching strength of the first transverse rib should be mainly concerned. This study can provide a reference for the engineering application and further research of geotextiles as reinforcement materials.