Objective: To explore application value of diffusion weighted imaging (DWI) in differential diagnosis of high-grade glioma and brain metastasis. Methods: 15 patients with high-grade glioma and 17 patients with single brain metastases confirmed by postoperative pathology were enrolled in this study. All the patients underwent routine craniocerebral MRI scan, enhancement scan and DWI. The apparent diffusion coeffecient (ADC) value of tumor parenchyma and peritumoral edema area, relative ratio of N-acetyl aspartate (NAA), choline (Cho) and creatine (Cr) in patients with high-grade gliomas and brain metastases were measured and compared. The receiver operating characteristic (ROC) curve was used to evaluate differential diagnosis value of DWI for high-grade glioma and brain metastases. Results: There was no significant difference in Cho/Cr, Cho/NAA, NAA/Cr and ADC value in tumor area between patients with high-grade glioma and single brain metastases (P>0.05). Compared with those in peritumoral edema area of single brain metastases, Cho/Cr and Cho/NAA were significantly higher in peritumoral edema area of high-grade glioma, while NAA/Cr and ADC values were significantly lower (P<0.05). The AUC, sensitivity and specificity of combined Cho/Cr, Cho/NAA, NAA/Cr and ADC value for differential diagnosis of high-grade gliomas and brain metastases were higher than those of singly application (P<0.05). Conclusions: The sensitivity and specificity of DWI are relatively higher for differential diagnosis of glioma and brain metastases, which is of relatively higher clinical application value.