Abstract Background:Total knee replacement is an effective treatment method in the terminal stage of rheumatoid arthritis and osteoarthritis,which has important effects in relieving pains and improving function. The two diseases have their own risk factors in the perioperative period. We compared risk factors with the two diseases after total knee replacement in order to provide clinical reference.Methods: This study included VAS scores, thigh circumcision, calf circumcision, blood loss, D-dimmer, FIB in 3 days after TKA surgery and statistical analysis was used by SPSS 21.0 software. The differences about swelling, blood loss, D-dimer and FIB were compared among postoperative patients.Results: Differences in VAS score, circumference of large and small legs, D-dimer, and FIB between the two sig>0.05 and blood loss sig<0.05. Conclusion: RA and OA due to the difference of pathogenesis, resulting in the two after TKA surgery has different risk factors, the study found that RA patients in TKA perioperative blood loss is higher than OA patients, the two in postoperative pain, size and leg swelling complications, there is no significant difference between the two D-dimmer, FIB indicators.