Background Henoch-Schonlein purpura (HSP) is a systemic small vessel vasculitis that is mainly caused by IgA1-type immune complex deposition. Advanced oxidation protein products (AOPPs) are specific markers of protein oxidation. Objective To explore the role of AOPPs in the pathogenesis of HSP. Methods There are 51 HSP patients who were divided into four subgroups: (i) skin type - 20 cases; (ii) joint type - 8 cases; (iii) abdominal type - 12 cases; (iv) renal type - 11 cases; and 18 healthy volunteers were enrolled as controls. The serum levels of AOPPs and Gd-IgA1 were quantified by an HAA-lectin-based ELISA. The Cosmc mRNA expression in peripheral B lymphocytes was measured by RT-PCR. Results 1. Advanced oxidation protein products in different subgroups of HSP patients are all higher than the controls, while the renal-type subgroup is the highest and the skin-type subgroup is the lowest. 2. Spearman correlation analysis shows that: (i) AOPPs and Gd-IgA1 in HSP patients are positively correlated; both of them are positively correlated with the disease severity scores; (ii) AOPPs are negatively correlated with the relative expression value (RQ) of Cosmc mRNA. Conclusion Advanced oxidation protein products play an important role in the pathogenesis of HSP, especially in renal-type patients.