Metallic materials are usually used in the geotechnical engineering; however, metallic materials would cause corrosion if they submerge or contact water and sometimes cause the damage of the geotechnical structures. FRP (Fiber Reinforced Plastics) composite materials have the merits of light weight, high strength, well-durability and other characteristics. In this study, FRP sheet piles were used to solve the corrosion problem of the geotechnical structures. First, the 3-point bending experiment was performed, and changing the span depth ration to obtain the specimen’s stiffness. Then, using the result of the experiment to feedback the finite element analysis model. In addition, changing the numerical model’s angle and thickness to investigate the stiffness and stiffness over cross section area. Finally, the specimen of 18-span depth ration whose displacement is more approach to Euler’s Beam theory from the experimental observation, and the error of numerical model’s result is less about 8.5 %. It’s prove that the analysis is almost exact. According to the numerical FRP sheet pile model, the 60°-angle FRP sheet pile is most economical betwwen 45°, 60° and 90°. Furthermore, the thickness of the 19.05 mm FRP sheet pile is more economical than the thickness of the 6.35 mm and 12.70 mm FRP sheet piles. Then, three kinds of sheet piles (FRP, PVC and steel) were modeled using Plaxis. We found that the PVC sheet pile has the lowest stiffness which causes its deflection concerns and a very low safety factor. On the other hand, the steel sheet pile enjoys the highest stiffness, lowest deflection and consequently, the largest safety factor. Furthermore, in order to improve the safety of the slope of the embankment, this study compares results of the the cantilever with the anchored FRP sheet pile. According to the results, the safety factor of the anchored FRP sheet pile is higher than cantilever one by 1.9 folds.