CD8+T cells are plentiful in rheumatoid arthritis (RA) and have a important role in it's pathogenesis. Many subsets have been identified in CD8+T cells, however, the relationship between CD8+T subpopulations and disease activity of RA is poorly defined. Here we detected different CD8+T cell subsets in peripheral blood and examined their relationships with clinical features and serological parameters in RA. CD8+T cell phenotypes and percentages in peripheral blood were determined by flow cytometry in 39 patients with RA. The clinical characteristics and serological parameters of RA patients were collected and DAS28-ESR was measured as indicator of disease activity. Linear regression was performed to assess the correlation of CD8+T cell subsets with RA clinical variables. Naive CD8+T cells were significantly and negatively correlated with RA disease activity indicator DAS28-ESR(r2=0.1027, p=0.0468), erythrocyte sedimentation rate (ESR)(r2=0.1891, p=0.0057), clinical disease activity index(CDAI)(r2=0.1474, p=0.0158), simplified disease activity index(SDAI)(r2=0.1465, p=0.0255), and duration(r2=0.1247, p=0.0274). And the percent of naive CD8+T cells were obviously decreased in RA with high disease activity when compared with RA in low disease activity(p<0.01). In addition, Our results indicated significant positive correlations between CD8+CD28- T cells and DAS28-ESR(r2=0.1881, p=0.0058), ESR(r2=0.2279, p=0.0021), c reaction protein (CRP)(r2=0.2203, p=0.0051), CDAI (r2=0.1778, p=0.0075), SDAI (r2=0.2618, p=0.0020), rheumatoid factor(RF)(r2=0.1823, p=0.0067), age(r2=0.1968, p=0.0047), as well as similar positive correlations between CD8+CD27- T cells and DAS28-ESR(r2=0.1661, p=0.01), ESR(r2=0.1586, p=0.012), CRP(r2=0.1778, p=0.013), CDAI (r2=0.1622, p=0.0110), SDAI(r2=0.2316, p=0.0040), RF(r2=0.2097, p=0.0034), age(r2=0.1932, p=0.0051). Furthermore, interesting results showed observable positive correlations between activated CD8+T cells and total cholesterol(TC)(r2=0.2757, p=0.0007), triglyceride(TG)(r2=0.2886, p=0.0005), low density lipoprotein(LDL-C)(r2=0.09643, p=0.0264) and Krebs yon denlungen-6(KL-6)(r2=0.4171, p=0.0002). And TCRγδ+CD8+T cells were also found positively related with total cholesterol(TC)(r2=0.5015, p<0.0001), triglyceride(TG)(r2=0.2031, p=0.0045), and KL-6(r2=0.2122, p=0.0136). Our results suggest that naive CD8+T cells, CD8+CD28- T cells, and CD8+CD27- T cells are obviously correlated with inflammation and disease activity of RA. While activated CD8+T cells and TCRγδ+CD8+T cells may involve in lipidmetabolism and lung fibrosis of RA. These CD8+T cell subsets may be new biomarkers and targets for RA disease evaluation, therapeutic target-selecting, curative effects and prognoses assessment.