In this present study, we investigated the association between asthma and two common SNPs (rs10399931 and rs4950928) of CHI3L1 in the southwest Chinese Han population and tried to identify the influence of rs10399391 on the allelic expression of CHI3L1. The CHI3L1 gene spans 7948bp with 10 exons in the human genome [14] and is a susceptibility locus for many diseases including cancer, autoimmune diseases, schizophrenia and chronic inflammatory diseases including asthma and chronic obstructive pulmonary disease [15]. The gene discussed is CHI3L1; the disease is chronic obstructive pulmonary disease.