〔Abstract〕 Objective To explore the evaluation value of musculoskeletal ultrasound in the active and inflammatory lesions of rheumatoid finger arthritis. Methods A total of 70 patients with rheumatoid finger arthritis admitted to Zhengzhou Central Hospital Affiliated to Zhengzhou University from September 2021 to May 2023 were selected as the research subjects. Different disease activity groups were divided according to the results of the rheumatoid athritis disease activity scoring system (DAS28). Musculoskeletal ultrasound diagnosis was performed on the finger of all patients. Image features of musculoskeletal ultrasound in patients with different disease activity were analyzed and semi-quantitative ultrasound scores were performed. Receiver operating characteristic (ROC) curve was established to analyze the efficacy of musculoskeletal ultrasound correlation semi-quantitative score in evaluating patients' disease activity. The levels of rheumatoid factor (RF), erythrocyte deactivation rate (ESR) and hypersensitive C-reactive protein (hs-CRP) related factors were compared in patients with different lesions diagnosed by musculoskeletal ultrasound. Spearman correlation was used to analyze the correlation between different lesions diagnosed by musculoskeletal ultrasound and inflammatory lesions. Results Of the 70 patients, 47 cases were active and 23 cases were in remission. There were 43 patients diagnosed with bone erosion, 62 patients diagnosed with joint effusion and 51 patients diagnosed with synovial hyperplasia. The scores of Joint effusion, bone erosion, intrasynovial blood flow signal, synovial thickening score and musculoskeletal ultrasound semi-quantitative in the remission group were significantly lower than those in the active group, with statistical significance (P < 0.05). The sensitivity and specificity of musculoskeletal ultrasound semi-quantitative score for evaluating the disease activity of rheumatoid digital arthritis were 83.23% and 94.14%, respectively. There was a significant difference in the levels of RF, ESR, and hs-CRP among patients with different bone erosion and joint effusion lesions (P < 0.05), while there was no statistical difference in the levels of RF, ESR, and hs-CRP among patients with different synovial hyperplasia (P > 0.05). The Spearman correlation analysis results showed that bone erosion lesions and joint effusion lesions were positively correlated with RF, ESR, and hs-CRP (P < 0.05), while synovial hyperplasia lesions were not significantly correlated with RF, ESR, and hs-CRP (P > 0.05). Conclusion Musculoskeletal ultrasound has high application value in evaluating the activity of rheumatoid finger arthritis patients. It can comprehensively reflect the inflammatory lesions of patients through joint effusion and bone erosion, and has important value in evaluating the condition and prognosis of rheumatoid finger arthritis.