Abstract: Objective To explore the capillary mechanism of hyperbaric oxygen(HBO)treatment on random skin flaps of rabbits.Methods Random skin flaps models were established on the back of rabbits and HBO treatment wss performed to rabbits in HBO group.The survival area of skin flaps,detected capillary density and contents of VEGF,HIF-1 on the 3rd day and the 7th day were observed,respectively.Results Compared with those in control group,there were statistical significances in the survival area of skin flaps and the content of VEGF in the HBO group on the 3rd day and the 7th day(P<0.01).The capillary density and the capillary density in the HBO group were higher than these in the control group on the 3rd day(P<0.05)and the 7th day(P<0.01),respectively.The content of HIF-1 in the HBO group wag lower than that in the control group on the 3rd day and the 7th day(P<0.05).Conclusions One of HBO treatment machanisons maybe that HBO can increase expression of VEGF,and further improve the survival rate of skin flaps.HBO treatment can decrease the expression of HIF-1 in skin flaps.