The invention relates to a deep sea microorganism in-situ enrichment apparatus, which belongs to the technical field of microorganism enrichment. The deep sea microorganism in-situ enrichment apparatus is initially in a closed state, when the apparatus is arranged on a specific position of deep sea, a hydraulic apparatus inside a shell drives a hydraulic rod to enable an end cover and an end coverto be opened, the apparatus is exposed in the seawater, the microorganisms inside the apparatus are adhered onto a place, which is provided for the microorganisms to adhere, of a substrate, solid culture medium which is rich in nutritional substances supplies nutrients to the microorganisms, temperature, pH value and rich elements inside the apparatus are detected by virtue of an environmental detection sensor and a temperature sensor on the inner wall of the shell, data is saved, after a sufficient time, the hydraulic apparatus drives the hydraulic rod to close the end cover and the end cover so as to seal the apparatus, the pressure and the temperature in the apparatus are ensured not to be changed, and the apparatus is taken to the shore and provided for the research personnel to research and analyze.