Objective: To investigate the safety of purified D. farina and D. pteronyssinus extract product Novo-Helisen-Depot (NHD) as subcutaneous immunotherapy (SCIT) in the children with mite allergy. Methods: We conducted a retrospective study analyzing the adverse events of the children undergoing subcutaneous immunotherapy with NHD. Adverse events included local and systemic adverse reactions (SRs) at the very early and late stage. The correlation of the basic characteristics, laboratory analysis results and the immediate/late local reaction (LRs) and systemic adverse reactions (SRs) were analyzed. Results: 287 patients received at least 15 months of subcutaneous immunotherapy with NHD were included in the analysis. Skin-prick testing (SPT) results of D. pteronyssinus was associated with an increased risk of immediate LRs in build-up phase (OR =1.53, 95% CI: 1.02,2.37) and delayed LRs in maintenance phase (OR =1.58, 95% CI: 1.05,2.46), while SPT results of D. farina was associated with an increased risk of SRs (OR =3.22, 95% CI: 1.17,10.00) and severe SRs (OR =7.68, 95% CI: 1.13,109.50). Serum IgE level of D. pteronyssinus was associated with an increased risk of SRs (OR =1.01, 95% CI: 1.00,1.03). Patients with both asthma and allergic rhinitis was associated with an increased risk of SR, and severe SRs ( P<0.05). Conclusion: NHD as SCIT is safe. The children with higher SPT level with D. farina or D. pteronyssinus, higher serum IgE level of D. pteronyssinus, children with both asthma and allergic rhinitis, and the children with treatment interruption had higher risk of adverse events.