Objective To investigate the level of serum soluble human stromelysin 2 (sST2) in the acute attack of bronchial asthma and its clinical significance. Methods We selected 128 patients with acute exacerbation of bronchial asthma as the study subjects in the observation group. In the same period, 100 healthy people in our hospital were selected as the control group. Serum levels of sST2, related inflammatory factors (IL-6, IL-10, hs-CRP, PCT) and immunoglobulin E (IgE) were compared between two groups. Results Compared with the control group, the serum levels of sST2, IL-6, hs-CRP, PCT and IgE in the observation group increased significantly, while serum IL-10 decreased significantly (P < 0.05); Pearson correlation analysis showed that sST2 was positively correlated with IL-6, hs-CRP, PCT and IgE (P < 0.05), but negatively correlated with IL-10 (P < 0.05); before treatment, serum sST2 level in severe asthma group was significantly higher than that in mild asthma group and moderate asthma group (P < 0.05). Serum sST2 level after treatment was significantly higher in severe asthma group, moderate asthma group and mild asthma group than that before treatment (P < 0.05), but the serum sST2 level in severe asthma group was still significantly higher than that in mild asthma group and moderate asthma group (P < 0.05). There was no significant difference between mild and moderate asthmatic groups (P > 0.05). Conclusions The serum sST2 level can reflect the severity of the acute attack of bronchial asthma to a certain extent. The assessment of patients' condition is of positive significance.