Ultral-High-b-value DWI (UHBV-DWI) was shown to improve the diagnostic performance of DWI in grading gliomas. We compare the value of MRI UHBV-DWI and conventional DWI for grading astrocytomas, and to analyze the correlation of respective parameters with aquaporin (AQP) expression. We found UHBV-ADC (0.810) showed a larger area under the curve (AUC) than that of ADC (0.713) (P < 0.05). The ADC value showed a negative correlation with AQP4 mRNA expression (r = -0.357; P = 0.024). UHBV-ADC value positively correlated with the AQP4 mRNA expression (r = 0.646; P ＜ 0.01). So UHBV-DWI allowed for a more accurate grading of cerebral astrocytoma as compared to DWI. UHBV-ADC may be related with the AQP4 mRNA levels.