【Abstract】 Objective To study the related factors of patients' aspiration caused by different tilt angles of wall buoy oxygen inhaler. Methods The commonly used inhalers were divided into repeatable disinfection humidification bottle group (group A) and disposable humidification bottle group (group B). Logistic regression analysis was used to analyze the water capacity, oxygen flow rate and inclination angle of the humidified liquid which led to the risk of spillage. Results When the inclination angle of group a ≤ - 70° or ≥85° and the inclination angle of group B ≤ -65° or ≥65°, overflow occurs in the humidifying bottle. In group A, when the inclination angle was 90° to 0°, the more water capacity of humidified liquid was, the higher the risk of overflow was (OR=1.435, P＜0.0001). The higher the oxygen flow rate, the higher the risk of spillage (OR=2.792, P=0.003). The higher the inclination angle, the higher the risk of spillage (OR=6.523, P＜0.0001). In group A, there was no correlation between the risk of overflow and the water capacity, oxygen flow rate and inclination angle of humidified liquid (P＞0.05). In group B, the smaller the rotation angle of outlet joint was, the higher the risk of spillage was (OR=0.994, P＜0.0001). The higher the inclination angle, the higher the risk of spillage (OR=1.173, P＜0.0001). In group B, the greater the rotation angle of outlet joint was, the higher the risk of spillage was (OR=1.007, P＜0.0001). The higher the inclination angle, the higher the risk of spillage (OR =1.143, P＜0.0001). There was no correlation between the risk of overflow and oxygen flow in group B (P＞0.05). Conclusion The wall buoy oxygen inhaler does have potential safety hazard in the process of use, and there is a risk of aspiration when the inclination angle of the inhaler is ≤-65 °or ≥ 65 °. In order to avoid this hidden danger, it is necessary to fix or limit the inclination range of the inhaler between -65 °and 65 °.