Abstract： Objective： To observe the clinical effect of modified Huagai Powder on pediatric bronchiolitis with wind-cold blocking lung syndrome. Methods：A total of 80 cases of children with bronchiolitis with wind-cold blocking lung syndrome，who were admitted to Changxing Hospital of Chinese Medicine from March 2022 to January 2025 were selected and divided into the observation group and the control group according to the random number table method， with 40 cases in each group. The control group was treated with routine western medicine，and the observation group was additionally treated with modified Huagai Powder based on the treatment of the control group. Both groups were treated continuously for one week. Clinical effects were evaluated in the two groups，and comparisons were made between the two groups regarding traditional Chinese medicine syndrome scores，lung function [tidal volume per kilogram （VT/kg）， peak time ratio （TPTEF/TE）， peak volume ratio （VPEF/VE）]， inflammatory factors [interleukin （IL）-4， IL-17， tumor necrosis factor- α （TNF- α）]， IL-33/ST2 pathway expression， and adverse reactions. Results： The total effective rate in the observation group was 95.00%（ 38/40），significantly higher than the 77.50%（ 31/40） in the control group （P＜0.05）. After treatment， traditional Chinese medicine syndrome scores in the two groups were decreased when compared with those before treatment （P＜0.05）， with the observation group showing lower scores than the control group （P＜0.05）. After treatment，VT/kg，TPTEF/TE，and VPEF/VE in the two groups were increased when compared with those before treatment （P＜0.05）， with the observation group showing higher values than the control group （P＜0.05）. After treatment， the levels of IL-4， IL-17， and TNF-α in the two groups were reduced when compared with those before treatment （P＜0.05）， with the observation group showing lower levels than the control group （P＜0.05）. After treatment， the levels of IL-33 mRNA and ST2 mRNA in the two groups were reduced when compared with those before treatment （P＜0.05）， with the observation group showing lower levels than the control group（ P＜0.05）. No significant difference was found in the incidence of adverse reactions between the two groups（ P＞ 0.05）. Conclusion： Modified Huagai Powder demonstrates definite efficacy in treating pediatric bronchiolitis with wind-cold blocking lung syndrome， which can promote symptom relief and reduce inflammatory responses. The mechanism may be related to regulation of the IL-33/ST2 pathway.