Objective:To observe the effect of hyperbaric oxygen (HBO) on peripheral hematopoietic stem cells (PHSCs) in a Chinese population, and to mobilize PHSCs by combined use of HBO and colony-stimulating factor (CSF) in an animal experiment. Methods: (1) The changes of CD34+ absolute count before and after HBO therapy were observed under routine HBO conditions in 8 patients who received long-term HBO therapy and 18 patients who received HBO therapy for neurological injuries. (2) Thirty BALB/c mice were equally randomized into three groups: HBO group, where the animals were exposed to HBO; HGF group, where the animals received recombinant hematopoietic growth factor injection; and HBO+HGF group. Postglobe venous blood was harvested before and after treatment; the gated cell CD34/Scal-1 dual-positive population was determined by flow cytometry. Results: (1) After 7 episodes of HBO therapies, the peripheral CD34+ absolute count of the patients rose from (1.87±1.08）×106/L before treatment to (4.75±4.67）×106/L(an increase of 2.54 folds); while the number was（2.85±1.94）×106/L after 14 episodes of HBO therapies (with an increase of 1.52 folds) and (3.26±3.49）×106/L after 20 episodes of HBO therapies (with a increase of 1.74 folds) . The peripheral CD34+ absolute count of the 8 patients who received long-term HBO therapy for neurological injuries was （2.11±1.14）×106/L, not significantly different from that of the 18 patients before treatment. (2) The gated cell CD34/Scal-1 dual-positive population in HBO group, HGF group, and HBO+HGF group after treatment were 2.01, 2.66, and 3.76 folds before treatment, respectively. Conclusion: Multiple HBO exposure can mobilize PHSC; prolonged HBO exposure fails to maintain the peripheral CD34+ absolute count at a relatively high level. Concomitant use of HBO and HFG can more effectively mobilize PHSCs.