Background: As an irreversible disease, a treatment delay can negatively affect treatment response in rheumatoid arthritis (RA). Ultrasound and MRI have played an important role in assessing disease progression and response to treatment in RA for many years. The present study was designed to compare the diagnostic efficacy of ultrasound grading and MRI in early RA. Methods: In this retrospective study, 62 early RA patients within 12 months of symptom onset were included. DAS28, rheumatoid factor (RF), CRP, ESR, and anti-cyclic citrullinated peptide antibody (CCP) of the patients were measured. Bilateral hand joints and wrists were examined by ultrasonography (US) and MRI; diagnosis outcome was compared. Relationship between DAS28 scores, laboratory parameters, and ultrasound findings were analyzed. Results: Ultrasound and MRI had an equivalent diagnosis value in synovitis, joint effusion, and tenosynovitis. The detection rate of synovitis, arthroedema, and tenosynovitis on ultrasound and MRI was very close (P > 0.05). The detection rate of bone erosion was lower in ultrasonography than that in MRI (P < 0.05). There were significant differences between power Doppler ultrasonography (PDUS) and gray-scale ultrasonography (GSUS) in the diagnosis of synovitis (chi(2) = 3.92, P < 0.05); the sensitivity of GSUS was better than that of PDUS (P < 0.05). PDUS was positively correlated with DAS28, ESR, CRP, and CCP (P < 0.01), but not correlated with RF and disease duration (P > 0.05). GSUS was positively correlated with RF and CRP (P < 0.01), but not correlated with DAS28, CCP, ESR, and disease duration (P > 0.05). Bone erosion was positively correlated with disease duration, CCP, and RF (P < 0.01) and was not correlated with DAS28, ESR, and CRP (P > 0.05). Conclusion: Ultrasonography has a high reliability in the diagnosis of early RA in synovitis, joint effusion, tenosynovitis, and bone erosion. Ultrasonography and clinical and laboratory parameters had a great correlativity. Both ultrasound and MRI are effective techniques. In view of the advantages of low cost and convenience, ultrasound may be a better choice during early RA diagnosis.