Objective To analyze the diagnostic value of MRI in injured meniscus of the knee. Methods MRI and arthroscopic findings of meniscus injury(116 menisci)in 49 cases were comparatively analyzed. Results Among 116 menisci of 49 knee joints,MR imaging showed 0 grade in 11, Ⅰ grade in 14, Ⅱ grade in 50, Ⅲ grade in 38(grade Ⅲa in 17 ,grade Ⅲ b in 11,grade Ⅲ c in 10),and Ⅳ grade in 3. Conclusion MRI is of important diagnostic value in meniscus injury of the knee.