Objective To analyze the relationship between rheumatoid factor（RF）,T lymphocyte subsets（CD3⁺,CD4⁺,CD8⁺,CD4⁺/CD8⁺）and the severity of rheumatoid arthritis．Methods A total of 90 patients with rheumatoid arthritis from January 2023 to April 2024 were selected as the observation group,and 90 healthy checkup individuals who came to the hospital during the same period were selected as the control group．All patients underwent RF,CD3⁺,CD4⁺,CD8⁺,and CD4⁺/CD8⁺ tests,and the severity of their condition was determined based on the evaluation of rheumatoid arthritis patient condition（DAS28）． Pearson Correlation analysis was used to analyze the relationship between RF,CD3⁺,CD4⁺,CD8⁺,CD4⁺/CD8⁺ and the disease severity of the patients．Results Compared with the control group,RF and CD8⁺ levels in the observation group were higher,while the levels of CD3⁺,CD4⁺ and CD4⁺/CD8⁺ were low（P<0.05）．Comparison of RF and CD8⁺ levels for different conditions,the RF and CD8⁺ levels of the severe patients was highest,followed by moderate and mild．However,the CD3⁺,CD4⁺ and CD4⁺/CD8⁺ levels were highest in mild patients,followed by the moderate and sereve patients．Statistical significance was found in both pairwise comparisons（P<0.05）．After the Pearson correlation analysis,RF and CD8⁺ levels were positively correlated with the degree of disease,while CD3⁺,CD4⁺,and CD4⁺/CD8⁺ levels were inversely associated with the degree of disease condition（P<0.05）．Conclusions RF and T lymphocyte subsets are closely related to the occurrence and development of rheumatoid arthritis,and can provide reliable references for physicians to accurately evaluate the severity of patients' conditions．