Objective To explore the clinical and MRI features of newly diagnosed patients with rheumatoid arthritis (RA) and the relationship between simple MRI score of wrist joint and disease activity. Methods 116 newly diagnosed RA patients admitted to our hospital from January 2023 to October 2023 were included. According to the DAS28-CRP score, the subjects were further divided into low activity group (DAS 28＜3.2) and middle activity group (DAS28≥3.2). The clinical and imaging features of patients were analyzed. According to the analysis results of MRI image features of two groups, the simple MRI score of wrist joints of RA patients was designed. Analyze the relationship between it and the activity of the disease. Results Compared with the low activity group, the high activity group of RA patients had older age at first diagnosis, longer course of disease, lower hemoglobin content, higher contents of rheumatoid factor, platelet count, high-sensitivity C-reactive protein, erythrocyte sedimentation rate, interleukin -6 and ferritin, and a larger proportion of anemia, with statistical significance (P＜0.05). In the middle and high mobility group, joint pain mainly involved hands (n=106, 91.38%), wrists (n=64, 55.17%), shoulders (n=49, 42.24%), ankles (n=32, 27.59%) and elbows (n= 64, 55.17%). Compared with the low mobility group, the high mobility group may have a higher rate of wrist involvement, with no statistical significance (P=0.052). Compared with the low mobility group, the high mobility group had higher shoulder joint involvement rate and lower foot joint involvement rate, and the difference was statistically significant (P＜0.05). There was no significant difference between the two groups in terms of hand, ankle, elbow and knee joint involvement (P＞0.05). The incidence of bone erosion and the rate of joint cavity stenosis in patients with middle and high activity were higher than those in patients with low activity, and the difference was statistically significant (P＜0.05). The number of synovial joints and bone erosion in each patient in the disease with high activity group were higher than those in the disease with low activity group, and the difference was statistically significant (P＜0.05). The swelling rate of soft tissue in patients with high activity may be higher than that in patients with low activity, and the difference is not statistically significant (P=0.058). The number of synovial involvement, bone erosion, joint cavity stenosis and soft tissue swelling in MRI were positively correlated with DAS28 score (r=0.320, 0.188, 0.288, 0.186, P＜0.05). Comparing the simple MRI scores of wrist joints between the two groups, it was found that the score of high activity group was significantly higher than that of low activity group, and the difference was statistically significant (P＜0.05). The simple MRI score of wrist joint was positively correlated with DAS28-CRP score (r=0.376, P＜0.05). Conclusion Combined with the clinical indicators and characteristics of patients with RA, the number and location of affected joints, the number of bone erosion, joint cavity stenosis and soft tissue swelling are all related to the disease activity of RA, and the simple joint MRI score can reflect the disease activity of RA, which is expected to be an index for evaluating the disease activity of RA patients