Objective To investigate the value of intravoxel incoherent motion DWI (IVIM-DWI) in differential diagnosis of high-grade gliomas and brain metastases.Methods Conventional MRI,contrast-enhanced MRI and IVIM-DWI were performed before surgery or chemoradiotherapy in 24 patients with high-grade gliomas and 28 patients with brain metastases.The diffusion constant (D),pseudodiffusion coefficient of perfusion (D*) and the perfusion fraction (f) in the parenchyma and peritumoral edema region within 1 cm and the normal centrum semiovale in the opposite side were measured,then the relative values of all parameters in each region (rD*,rD,rf) were calculated.Independent sample t test was used to analyze the parameters.ROC curve analysis of the parameters statistically different between high grade gliomas and brain metastases were performed,and the diagnostic efficacies were evaluated.Results The D* and rD* values of tumor parenchyma and in peritumoral edema within 1 cm of high-grade gliomas were higher than those of brain metastases (all P＜0.05).The f and rf values of tumor parenchyma and in peritumoral edema within 1 cm of highgrade gliomas were lower than those of brain metastases (all P＜0.01).The AUC of D* value in peritumoral edema within 1 cm was the highest,but there was no statistically different between any two AUC except the rD* value of peritumoral edema within 1 cm (P =0.033).Conclusion IVIM-DWI can distinguish the differences of diffusion and perfusion information in parenchyma and edema area between high-grade gliomas and brain metastases,therefore providing the basis for differential diagnosis of them.