OBJECTIVE To investigate the effect of subcutaneousimmunotherapy(SCIT) on levels of the serum human beta defensin-2 in children with allergic rhinitis. METHODS 30 cases of children with allergic rhinitis who were treated by SIT were selected as the treatment group, 20 cases of healthy children as the control group. Serum HBD-2 concentration of the control group was tested. Serum HBD-2 concentration of the treatment group was tested at three different time points: before SCIT, half a year after SCIT and one year after SCIT. And total nasal symptom scores(TNSS) and medication scores were recorded at each time point. RESULTS The serum HBD-2 concentration of the control group, that of the treatment group before SIT, half a year after SIT and one year after SIT were 4.62[4.08; 4.87], 3.74[3.37; 4.61], 4.62[4.13; 5.54], 4.79[4.45;6.19]ng/ml. The HBD-2 concentration gradually increased after SCIT. The TNSS of the treatment group before SCIT, half a year after SCIT and one year after SCIT were 7.43±2.15, 4.17±2.16, 4.20±1.92, The medication scores of the treatment group before SCIT, half a year after SCIT and one year after SCIT were 1.25[0.75; 1.38], 0.25[0; 0.75, 0.25[0; 0.75].There was no correlation (all P>0.05) between the serum HBD-2 concentration and TNSS or medication scores of the treatment group. CONCLUSION The serum levels of HBD-2 in patients with allergic rhinitis were lower than those in normal persons. The specific immunotherapy raised the serum HBD-2 levels of allergic rhinitis patients.