There is no unified standard for the clinical typing of chronic duration of bronchial asthma.We have preliminarily explored the traditional Chinese medicine clinical phenotype of this disease and found significant differences in the expression and distribution of single nucleotide polymorphism(SNP) and methylation genes between deficiency-cold syndrome and deficiency-heat syndrome.Here we expound the theoretical basis and pathogenesis of chronic duration of bronchial asthma with the deficiency-cold syndrome.