The invention discloses a device for pressure maintaining transfer of a high pressure fluid sample. The device mainly comprises a culture barrel, a sampling barrel, a culture barrel constant pressure module, a middle pressurization and additive input module and a sampling barrel driving module. According to the device, the pressure maintaining transfer of the high pressure fluid sample after deep sea water body sampling can be performed, so as to perform later period culture experiments on the water body sample after the transfer. Unique structural design is adopted to achieve an equipressure transfer technology, a gas phase of the high pressure water body sample, an organic group and barophilic microorganisms and the like are maintained, dissolved gas and liquid in the sample are not separated from each other, it is guaranteed to the largest extent that the environment is unchanged in the sample transferring process, and the authenticity of sample detection data undergoing follow-up laboratory aftertreatment is improved.