An underwater sample dry-wet transformation and transfer device comprises a manned cabin. A dry-wet transformation and transfer device body is installed at one end of the manned cabin and structurally comprises a transformation cabin barrel; transformation cabin port covers are installed at the two ends of the transformation cabin barrel correspondingly; a slide rail is installed on the inner wall of the transformation cabin barrel, a sample holder is installed on the slide rail, and sampling barrels are arranged on the sample holder; a vent valve is installed on the transformation cabin port over at one end of the transformation cabin barrel, an exhaust valve is installed on the transformation cabin port cover at the other end of the transformation cabin barrel, and a pressure gauge is installed at the top of the transformation cabin barrel; and the top of the transformation cabin barrel is connected with an inflation pump located in the manned cabin, and the bottom of the transformation cabin barrel is connected with a water pump located in the manned cabin. By adoption of the underwater sample dry-wet transformation and transfer device, underwater samples obtained through underwater vehicles including an ROV and the like can be sent to the manned cabin carrying a detecting device in time for real-time analysis, a sampling task is adjusted according to real-time analysis data, and the sampling efficiency of the underwater vehicles including the ROV and the like is improved.