Objective: To evaluate the correlation between low field strength MRI and/or color flow doppler imaging(CDFI) and the arthroscopic or intra-operative staging of cartilaginous degeneration of knee joints. Methods: Fifity eight patients for knee joint arthroscopic examination or operation were included. A total of 290 articular surfaces were examined by low filed MRI to evaluate the lateral and medial epicondyle of femur,the intercondylar fassa,and the lateral and medial slope of trochlea. Among them,32 joints were received CDFI examination. Results of MRI and CDFI examination were comparied with that of arthroscopic examination. Results: Taken the arthroscopic examination as gold standard,the correlation index of MRI and CDFI was 0.800(P < O.05) and 0.667(P < O.05),respectively,while combined MRI with CDFI,the correlation index was 0.821(P < 0.05). Conclusion: Both low field MRI and CDFI have good correlation with arthroscope in the diagnose and staging of cartilaginous degeneration of knee joints. The correlation index of combination is higher than single modality. These results implied a role of low field MRI and CDFI in the diagnosis and preoperative assessment of cartilaginous degeneration of knee joints