Abstract: Objective To investigate the effects of two semi recumbent angle combined with lateralposition on incidence rate of pressure ulcer in patients with non-invasive ventilation.Methods A total of 130 patients were randomly divided into two groups.Group A was given 45 degrees semi supine,group B was given 30 degrees semi supine,and both groups were treated with lateral position.Incidence of pressure ulcer was observed in both groups.Results There were no significant differences in the incidence rate of pressure ulcer and satisfaction degree between two groups (P ＞ 0.05).There were significant differences in mechanical ventilation time and caudal temperature between two groups (P ＜ 0.05).Conclusion Two kinds of semi recumbent angle combined with lateral decubitus nursing can be used for patients with non-invasive ventilation.