The development of FRP septic tanks can be roughly divided into three stages: in the first stage, the products are square. If separated, it is an upper and lower trapezoid. When processing, two trough-shaped models are processed first, and then put together to become the finished product. This product solves the shortcomings of radical products, such as non-corrosion, easy to leak and block, but the sealing is not good enough and the pressure resistance is average, so it is impossible to make large-scale products. But the top and bottom are still designed to be flat. Start using the wheel-shaped concave-convex head. Because it is a cylindrical mold, the products in the second stage are basically horizontal cylinders. The products at this stage are generally connected and combined by docking. The compression resistance of the product is better than that of the first stage, but the compactness of the product is acceptable, and the processing procedure of the product is complicated, which is beneficial to industrial production. The corrugated horizontal cylinder is molded once, and the product in the third stage is corrugated FRP septic tank. The two ends are designed with concave and convex surfaces and have mechanical properties. Unique circumferential dense corrugated structure design, compressive strength and impact strength are improved several times, such as cylindrical strength, spherical arch strength and so on. And can meet the needs of different situations without any other reinforcement measures. At present, the comprehensive performance of products is at the international advanced level.