Abstract: Objective: To investigate the relationship between glucose-6-phosphate isomerase（GPI） and therapeutic effect in patients with rheumatoid arthritis by measuring the level of serum GPI before and after the therapy. Methods: The serum levels of GPI and RF in 51 rheumatoid arthritis patients and in 30 healthy controls were tested and analyzed before and after the therapy. Results: The serum level of GPI and positive rates of RF in RA patients were significantly higher than those in healthy controls（P＜0.001）;and those in active rheumatoid arthritis group were significantly higher than those in non-active group（P＜0.001）.When the disease was controlled after the therapy,the serum level of GPI decreased significantly. Conclusion: The increased GPI level in RA patients is related to the activity of arthritis.Serum level of GPI could be recognized as an indicator of RA remission after treatment.