Abstract: Objective To examine the oxidation or reduction products in patients with rheumatism arthritis (RA), and inves-tigate the relationship between oxidation or reduction products and occurrence and development of RA. Methods The serum levels of total ascorbic acid (TAA), dehydroascorbic acid (DHAA)/TAA, vitamin E, advanced oxidation protein products (AOPP) and malondialdehyde (MDA) were detected by high-performance liquid chromatography with electrochemical detection in 83 RA patients and 30 healthy adults. Correlation analysis of AOPP, MDA and hs-CRP was performed. Results Compared with normal control group, significantly higher serum MDA, DHAA/TAA, and AOPP levels were detected in RA patients (P<0.05), but vitamine E showed no significant difference (P<0.05). Linear regression analysis showed that MDA (P<0.01) was positively but AOPP (P>0.05) negatively correlated to hs-CRP. Conclusion Oxidation or reduction products in serum of RA patients increases significantly, which may be an important mechanism for the occurrence and development of RA. Serum AOPP and MDA levels can reflect the oxidation status in RA patients.