Tool-free PCIE or GPU fixing device and disassembly and assembly method

The embodiment of the invention discloses a tool-free PCIE (Peripheral Component Interconnect Express) or GPU (Graphics Processing Unit) fixing device and a disassembly and assembly method, the tool-free PCIE or GPU fixing device comprises a server case, at least two card pressing structures and a card pressing piece, the card pressing structures are arranged on two sides of the server case, the card pressing piece is arranged in the server case, each card pressing structure comprises a rotating part and a positioning part, and the rotating parts are arranged on the rotating parts. The rotating part is movably connected with the positioning part, an unlocking unit is arranged on the rotating part, and when the rotating part and the positioning part are clamped, the rotating part and the positioning part are locked to form a buckle structure, so that the pressing and clamping structure presses the pressing and clamping piece, and the unlocking unit is arranged on the rotating part. Compared with a traditional