The invention discloses a device and a method for treating saline organic wastewater by adopting deep sea microorganisms. The device comprises a bacterial liquid reservoir (1), a bacterial liquid and wastewater mixture reaction area (2), a microorganism biochemical reaction area (3) and a negative pressure area (4), wherein the bacterial liquid reservoir (1) is communicated with the bacterial liquid and wastewater mixture reaction area (2) by means of a bacterial liquid inlet pipe (2-1); the bacterial liquid and wastewater mixture reaction area (2) is separated from the microorganism biochemical reaction area (3) by means of a conductive spacer plate, and a fluid flow passage from the bacterial liquid and wastewater mixture reaction area (2) to the microorganism biochemical reaction area (3) is arranged while the bacterial liquid and wastewater mixture reaction area (2) is separated from the microorganism biochemical reaction area (3); the negative pressure area (4) is a space positioned at the upper part of the bacterial liquid and wastewater mixture reaction area (2) and the microorganism biochemical reaction area (3). The method comprises the following steps: enabling the saline organic wastewater and bacterial liquid to separately flow into the bacterial liquid and wastewater mixture reaction area according to different ratios, mixing and then treating in the microorganism biochemical reaction area.