Objective To investigate the efficacy and safety of conventional therapy combined with ventilator assisted therapy for children with severe bronchiolitis. Methods 110 children with severe bronchiolitis treated in our hospital from June 2015 to June 2017 were selected and randomly divided into control group and observation group, respectively. The control group was treated with relieving cough and asthma, routine anti-infection, atomization suction, and glucocorticoid symptomatic treatment. On this basis, the observation group was treated with ventilator assisted therapy. Blood gas analysis was carried out before and after treatment, and the symptoms and signs subsided time, and the serum inflammatory factor levels were compared. The clinical efficacy were evaluated, and the incidence of complications were compared. Results The total effective rate of the observation group was 92.73%, which was significantly higher than that of the control group (81.82%), the difference was statistically significant (P＜0.05). Before and after treatment, PaO2, PaCO2 and PaO2 / FiO2 were significantly different between the two groups (P＜0.05); And the difference between the observation group and the control group at 6h, 1d and 2d after treatment was statistically significant (P＜0.05), while the blood PH value was no significant difference (P＞0.05). The recovery time of breathing and heart rate, and the disappearing time of the lung rales, wheezing and cough in the observation group were significantly shorter than those in the control group (P＜0.05). There was no significant difference in the incidence of complications between the two groups (P＞0.05); The serum inflammatory factor levels were decreased after treatment, and the serum TNFα, IL-4 and IL8 levels were lower in the observation group than in the control group (P＜0.05). Conclusion The conventional therapy combined with ventilator assisted therapy is an effective and safe way to ameliorate hypercapnia and the respiratory symptoms such as cough and wheezing for children with severe bronchiolitis.