Objective: To explore the effect of different air pressure treatment time on preventing deep vein thrombosis in severe chronic bedridden patients. Methods: This is a prospectie, randomized and controlled study. A total of 120 patients with severe chronic bedridden were randomly divided into normal group and experimental group 1, group 2, with 40 cases in each group. The normal group received 30 min every time, and group 1 received 1h,and group 2 received 2h. To observe the incidence of DVT within 15 days, the blood flow velocity of deep femoral vein before and after the first treatment, and the incidence of deep tissue injury. Results: There was no significant difference in the incidence of DVT among the three groups (P> 0.05), but the incidence of DVT in test group 1 was 5.0% (2/40), 2.5% (1/40) and 12.5% (5/40) compared with the conventional group. Compared with before treatment, the blood flow velocity of deep femoral vein in the three groups increased significantly after treatment (t=1.475、t=2.881、t=4.027, all P < 0.05), but after treatment, the blood flow velocity of deep femoral vein in the conventional group (20.41±1.37) ml/s, the experimental group 1 and the experimental group 2 were (22.39±2.22) ml/s and (22.51±1.73) ml/s, respectively, which were significantly faster than that of the conventional group. There were significant differences (t= 3.086、t= 3.662, all P < 0.05).(3) The incidence of deep tissue injury in experimental group 2 was 20.0% (8/40), which was 2.5% (1/40) and 5.0% (2/40) higher than that in conventional group and experimental group 1 respectively (χ2=6.135、χ2=4.114, all P<0.05). Conlousion On the basis of conventional barometric therapy, it can be extended to 1 h/time, 3 times/d, which can significantly increase the blood flow velocity of deep femoral vein, reduce the incidence of DVT, and do not increase the incidence of skin pressure injury in patients with chronic bed-rest. It is worth popularizing and applying in clinic.