Therefore, we selected 10 tagSNPs of the CHI3L1 gene using Tagger pairwise methods, explored the association between the CHI3L1 gene and asthma risk, and measured decreased lung function with forced expiratory volume in the first second of the forced vital capacity (FEV1) and forced vital capacity (FVC), which are regarded as indicators of asthmatic symptom severity. This evidence concerns the gene CHI3L1 and asthma.