Abstract: Objective To study the effects of hyperbaric oxygen on the diastolic heart failure in hypertensive patients. Methods 60 hypertensive patients with diastolic heart failure were randomly divided into treatment group and control group. Conventional therapies were given to patients of both groups. In addition, hyperbaric oxygen therapy was applied to those of treatment group. After 3 months, Doppler ultrasound recordings were obtained from all patients to determine the left ventricular diastolic function. Results The indexes of left ventricular diastolic function were im-proved after treatment in both groups(P < 0.01) ,and treatment group was better than control group(P < 0. 05). Conclusion For hypertensive patients with diastolic heart failure, hyperbaric oxygen can improve heart diastolic function.