Abstract: Objective To investigate the level and structure of polyunsaturated fatty acid (PUFA) of Chinese elderly population and analyze the relationship between the level of polyunsaturated fatty acids and inflammatory and immune biomarkers. Methods One hundred and sixty-eight elderly people (more than 70 years old) who had undergone health examination in Chinese PLA General Hospital in 2014 were selected. The content and construction of ω-3 PUFA and ω-6 PUFA in blood samples were detected using high performance liquid chromatography-mass spectrometry (HPLC-MS). The lymphocyte subsets, inflammatory cytokines and the level of C-reaction protein (CRP) were detected and the relationship between polyunsaturated fatty acid and immune inflammation was analyzed. Results The level of ω-3 PUFA, EPA, DHA and ω-3 index was 5.68%±2.01%, 0.32%±0.21%, 3.27%±1.10% and 3.59%±1.18%, respectively. The total ω-6 PUFA was 26.76%±4.56%, and the ratio of ω-6 and ω-3 was 5.56±2.77. IL-2 was negatively correlated with EPA, DHA and ω-3 index (r_EPA= -0.153 2, r_DHA= -0.305 5, r_ω-3index= -0.319 5, P＜0.05), PGE₂was negatively correlated with EPA and ω-3 index (r_EPA= -0.167 8, r_ω-3index= -0.245 8, P＜0.05), and COX-2 was negatively correlated with AA (r_AA= -0.167 7, P＜0.05). While, fatty acids were not correlated with lymphocyte subsets. Conclusion The elderly population enrolled in this study is lacking of ω-3 PUFA which has anti-inflammatory effects to our body.