Objective To assess the activity of Crohn’s disease (CD)by using the quantitative parameter of dynamic contrast-enhanced MRI (DCE-MRI).Methods 50 CD patients with ileocecal solitary lesion were recruited in this study.All of patients underwent con-ventional and DCE-MRI.The quantitative parameter of volume transfer constant (Ktrans )and the clinical data including Harvey-Brad-show index (HBI)and C-reactive protein (CRP)were recorded.(1)the reliability and repeatability of Ktrans measurement were analyzed. (2)the correlation between Ktrans value and clinical data was analyzed by using Pearson analysis.(3)according to HBI,all of the CD patients were divided into severe group,mild-moderate group,and static group.The differences of Ktrans values among the three groups were compared by using Mann-Whitney U test.Results (1)the reliability of Ktrans measurement was high (Cronbach’s Alpha=0.993).(2)there was positive correlation between HBI and Ktrans(r=0.635,P<0.001),and between CRP and Ktrans(r= 0.764,P<0.001).(3)there was significant difference of Ktrans value between the static group and the mild-moderate group (P<0.001),be-tween the static group and the severe group (P<0.001),and.between the mild-moderate group and the severe group (P<0.001). Conclusion Quantitative parameter of DCE-MRI (Ktrans )had a high reliability and can be used to assess the inflammation activity of CD.