Abstract: Objective To assess the relation between severity of meniscus injury and T2 value of knee joint cartilages. Methods Ninety osteoarthritis (OA) patients (168 menisci) who underwent conventional MRI and T2-mapping were retrospectively analyzed.The patients were divided into control group (n=15) with grade 0 meniscus injury and patients group (n=65) with gradesⅠ, Ⅱ, Ⅲ meniscus injury. T2 values of medial femoral and lateral condyle cartilages, and medial tibial and lateral condyle cartilages adjacent to the center of meniscus posterior horn were measured. Relation between severity of meniscus injury and T2 values of knee joint cartilages was studied. Results No significant difference was found in T2 values of knee joint cartilages between patients with grade Ⅰ/Ⅱ meniscus injury and controls (P=0. 53, P=0.99). The T2 values of knee joint cartilages were significantly higher in patients with gradeⅢmeniscus injury than in controls and in patients with gradeⅠ/Ⅱ meniscus injury (P＜ 0.05). Signals were observed in medial meniscus posterior horns of 61.7% patients (29/47) with grade Ⅲ meniscus injury. The T2 values of medial tibial and femoral cartilages were significantly higher than those of lateral tibial and femoral cartilages in patients with gradeⅢmeniscus injury (P＜ 0.05). Conclusion The T2 values of knee joint cartilages are significantly higher in patients with gradeⅢmeniscus injury. T2-mapping plays an important role in diagnosis of knee joint cartilage injury.