Background; As a result of the finding that the mutation of Arg into Gly at β2-adrenergic receptor(β2-AR)16 loci could promote the downregulation effect triggered by the β2-agonist, it was supposed that Gly16 might be associated with the downregulation of β2-AR in patients with nocturnal asthma. Objective; It was the aim of this study to analyze the association between β2-AR genetic polymorphisms and nocturnal asthmatic patients of Chinese Han nationality. Methods; A polymerase chain reaction allele-specifi c oligonucleotide hybridization assay was used to determine 16 and 27 loci alleles of β2-AR genetic polymorphisms in 25 nocturnal asthmatic patients(nocturnal asthma group), 22 non-nocturnal asthmatic patients(non-nocturnal asthma group), and 72 healthy people(control group). All people investigated were of Chinese Han nationality. Results; The distribution frequency of genotype Arg/Arg, Arg/Gly, and Gly/Gly at β2-AR 16 loci was 12, 16 and 72% in the nocturnal asthma group; and 27, 41 and 32% in the non-nocturnal asthma group. There was a signifi cant increase in the frequency of genotype Gly/Gly and allele Gly in the nocturnal asthma group compared with the non-nocturnal asthma group(p<0.01). However, there was no signifi cant difference in the frequency of genotype Gly/Gly and allele Gly in the non-nocturnal asthma group, compared withthe control group. There was no signifi cance in the frequency of the genotypes and alleles of β2-AR 27 loci among the three groups(p>0.05). Conclusion; The Gly16 polymorphism of β2-AR was overrepresented in nocturnal asthmatic patients, correlated with nocturnal asthma, and therefore appeared to be an important genetic factor in the expression of this asthmatic phenotype.