Objective: To explore the performance of MRI intravoxel incoherent motion diffusion weighted imaging（IVIM-DWI） parameters in diagnosing active Crohn′s disease(CD). Methods: The MRI IVIM-DWI scan was performed on 30 patients with active ileocolonic CD diagnosed by endoscopy. The IVIM-DWI parameters, including apparent diffusion coefficient（ADC）, diffusion coefficient of the true water molecule （D）, microcirculation perfusion coefficient （D*） and perfusion fraction（f）, within the walls of involved ileocolon (CD group ) and normal intestinal at the same level (control group) were determined. The parameters were compared between CD and control groups. Receiver operator characteristic(ROC) analysis was performed to evaluate the diagnostic performance of each parameter. Results: ADC, D* and f values in CD group were significantly lower than those in control group (P<0.05). There was no statistically significant difference in D values between the two groups(P>0.05). The optimal cut-off value of ADC, D*, f for diagnosing CD were 1.00×10^-3 mm²/s, 26.50×10^-3 mm²/s, 40.4%, with the area under the ROC curves of 0.952, 0.726, 0.799, respectively. Conclusion: MRI intravoxel incoherent motion diffusion weighted imaging （IVIM-DWI） parameters, such as ADC, D*and f values, are helpful for diagnosis of active CD, and ADC value has the highest diagnostic performance.