The utility model relates to a seabed sampling device, in particular to a bolt-free gravity piston type columnar sediment fidelity sampler without bolt, which comprises a fidelity sampling cylinder, a diversion cabin, an energy accumulator, a sealed cabin, a counter weight mechanism, a lifting frame and the like. The diversion cabin is fixedly sleeved on the upper end of the fidelity cylinder, the sealed cabin is movably sealed on the fidelity cylinder and is separated from the diversion cabin; the lifting frame comprises a clamp plate, a piston, a main cable and a sealed cabin cable, wherein the main cable penetrates through the clamp plate and is connected with the piston in a lining cylinder, and the sealed cabin cable penetrates through the clamp plate and is connected with the upper end of the sealed cabin. Based on the optimization of the sampling diameter, the utility model increases the sampling depth. Due to the structure without the bolt, the utility model prevents the sample pressure maintaining failure caused by the mistaken action of the bolt. Based on the technology of water washing of the isolated bulkhead, the utility model can improve the sealing performance of the lower seal port of the sealed cabin.