Objective To study the seasonal change of antibodies levels in the serum of asthma patients and Der P1 concentration in the dust samples collected from their bedrooms. Methods 36 asthma patients who were allergic to mites were treated as the patients group,21 male and 15 female,aged 43 years of average age. 20 healthy individuals were treated as the control group,11 male and 9 female,with the same age as the patients group. In September and December in 2005,and Match and June in 2006,the dust samples in the bedrooms of patients and the venous blood were collected,the samples of the control were collected only in September. Der P1 concentrations in dust samples and the levels of total IgE,mite specific IgE (s-IgE),s-IgG1,s-IgG2,s-IgG3 and s-IgG4 were detected by ELISA assay. Results In autumn,the levels of total IgE,s-IgE,s-IgG1,s-IgG2,s-IgG4 and the Der P 1 concentrations in patients were significant higher compared with the control group (P