Abstract: The steel-disk floating roof, assembled-aluminum floating roof, metal framework and plastic floating roof are generally used in oil tanks. The three-proof floating roof (squeeze-proof, sink-proof, leak-proof) has been further improved on the basis of the above mentioned roofs. In particular, the honeycombed, framework or lattice design forms for integral structure with high-strength aluminum-alloy or stainless steel and active joint connections can guarantee the floating roof's strength, rigidity reliability and assembly accuarcy. This paper introduces the structural and technical features of the three-proof floating roof.