Abstract: 　Objective　To evaluate the efficacy and influencing factors of 3% hypertonic saline (HS) inhalation in treatment of bronchiolitis. Methods　Clinical data together with the detection of 16 types of respiratory tract virus from hospitalized pediatric patients with primary diagnosis of bronchiolitis from June 2009 to December 2012 were retrospectively analyzed. The endpoint indicators for evaluation on the efficacy of nebulized 3% HS inhalation were the percent decrease of clinical severity (CS) score after 2 days' treatment and the hospitalization time. Factors affecting efficacy were further explored. Results　The CS score in nebulized 3% HS treated group decreased in average of 42.86% (11.11%-66.67%), significantly higher than that (26.79%, 0.00%-50.00%) in the untreated group (P=0.006). No difference of between the two groups (P=0.26). Multiple linear regression analysis showed that nebulized 3% HS inhalation has better efficacy on the patients older than 3 months having breastfeeding, respiratory synthetic syncytial virus (RSV) infection and extensive wheezing sound auscultation of the lungs. The multiple linear regression analysis model was statistically significant (R2=0.58, P < 0.001). Conclusions　After 2 days' treatment with 3% hypertonic saline inhalation, the CS score of bronchiolitis patients was decreased. The treatment can be recommended in hospitalized patient older than 3 months with breastfeeding, RSV infection, and extensive wheezing sound auscultation of the lungs.