To evaluate the utility of apparent diffusion coefficient (ADC) data obtained from ultra-high b-values in renal function using with rat model of unilateral ureteral obstruction (UUO). We compared the differences of ADCuh among time points and between the sides, and determined the correlation of ADCuh with positron emission tomography (PET) renal function and expression of aquaporin 2 (AQP-2). ADCuh of the UUO sides on day 0 was significantly lower than that of on day 1, 3, 5 and 7. ADCuh was negatively correlated with SUV both on the UUO side and contralateral side. Therefore, ADCuh may have a certain value to help evaluate renal function.