In dykes with fabriform sand, friction often exists between two adjacent geotextile bags and between a geotextile bag and the sand, and the transverse tension and the longitudinal tension of the geotextile bag are anisotropic. Based on these characteristics, a three-dimensional finite element method was used to simulate a dyke with fabriform sand, and the experimental data were adopted to analyze the stability of the dyke and its influencing factors. The results show that the integral safety factor increased significantly as the tensile strength of the geotextile bags and the filled soil strength increased. As the depth of the filled soil increased, the integral safety factor decreased rapidly at first, and then tended to become stable.