Objective: To evaluate the clinical value of MRI, CT and X-ray in the early diagnosis of Rheumatoid arthritis (RA). Methods: 89 patients with RA admitted to our hospital from May 2019 to February 2024 were retrospectively collected as the test group, and another 87 patients with normal RA results were selected as the normal group. To compare the diagnostic value of MRI, CT and plain X-ray in the early lesions of the wrist in patients with RA, the results of joint ultrasound were used as the diagnostic gold standard. The results of synovial thickness measured by three methods were compared. The imaging findings of MRI, CT and X-ray were observed and analyzed. Results The sensitivity, specificity and accuracy of MRI were 83.15%, 72.41% and 78.40%, respectively, which were significantly higher than those of CT and plain X-ray examination. Among the 89 RA patients, 178 wrist joints showed different degrees of synovial thickening. The synovial thickness was found to be (3.87±1.67) mm by MRI, (3.41±1.31) mm by CT, and (3.01±1.01) mm by X-ray plain film. MRI, CT and X-ray examination showed that the difference of synovial thickness was statistically significant (F=17.90, P<0.05). Among 89 RA patients, 178 wrist joints were involved by MRI, CT and X-ray. MRI showed swelling and exudation of the surrounding soft tissues in 42 wrist joints, a small amount of effusion in 31 wrist joints, and insect erosion of bone edges in 67 wrist joints. CT examination showed that 38 wrist joints had soft tissue swelling and exudation, 26 wrist joint space widening, and 59 wrist joint bone defect. Plain X-ray examination revealed increased periarticular density or blurred contour in 34 wrist joints, a small amount of fluid in 29 wrist joints, and irregular articular surface in 55 wrist joints. Conclusion MRI, CT and plain X-ray examination can provide comprehensive and intuitive tomography images for RA joint lesions, but MRI examination is more accurate in the early clinical diagnosis of RA joint lesions.