Method for improving single-layer oil tank into double-layer oil tank

The invention relates to a method for improving a single-layer oil tank into a double-layer oil tank. On the basis that the inner wall of the buried single-layer steel oil tank in service is derusted, an anti-corrosion reinforcing coating, a 3D through gap layer and a glass steel inner tank are sequentially manufactured, and the single-layer oil tank is quickly improved into the glass steel double-layer oil tank with a through gap layer space. The 3D through gap layer is communicated with a tank top monitoring well, and sealing performance of the inner tank and the steel outer tank in service can be monitored all day long. The inner surface of the glass steel inner tank is coated with an anti-static layer which makes direct contact with stored liquid, the anti-static layer is connected with an original steel storage tank, and the original steel single-layer storage tank is grounded so that electrostatic hazards can be avoided. The inner tank is made from a glass steel material formed by mixing resin and glass