The invention discloses a simple disassembling method of a sealing mechanism of an O-shaped sealing ring, which comprises the steps of: 1. drilling a plurality of technical screwed holes in a circular bump of a first cabin section; 2. screwing a technical screw from one end of each technical screwed hole to the first cabin section respectively in each technical screwed hole; and 3. leaning against the end of a second cabin section which leans against the side wall of the circular bump respectively through each technical screw so as to separate the second cabin section from a cylindrical groove of the first cabin section. According to the simple disassembling method of the sealing mechanism of the O-shaped sealing ring, the sealing structure of the O-shaped ring between two large steel pieces is disassembled in a screw leaning manner, so that the problem of no disassembling devices can be solved effectively. The simple disassembling method of the sealing mechanism of the O-shaped sealing ring is a technology, large heavy parts can be separated by the method, and the method can be applied to separation process where parts in tight fit are hard to disassemble. The simple disassembling method of the sealing mechanism of the O-shaped sealing ring provided by the invention has the advantages of simple process, operation convenience, safety and reliability, and low manufacturing cost, and is specially suitable for disassembling the O-shaped sealing ring sealing device.