Purpose Clear cell renal cell carcinoma (CCRCC) is the most lethal malignant urologic tumor. The Fuhrman grading system is an independent indicator for aggressiveness and prognosis of CCRCC. Our goal is to assess the possible diagnostic role of biexponentially and monoexponentially fitted signal attenuation for the Fuhrman grading. Materials and methods A total of 33 patients with CCRCC underwent multiple b values (0, 20, 50, 100, 150, 250, 400, 600, 800, 1000 s/mm2) diffusion-weighted imaging (DWI). Biexponential parameters fast ADC (ADCf), slow ADC (ADCs) and fraction of ADCf (f) , monoexponential apparent diffusion coefficient (ADC) were calculated, and correlated with the Fuhrman grade of CCRCC respectively. The receiver operating characteristic (ROC) curves were used to assess and compare the performance of biexponential parameters and ADC value in differentiating Fuhrman low- and high-grade tumors. Results: Qualified images and diffusion weighted parameters were obtained for all patients. The ADCf and f value were positively correlated whereas ADCs and ADC value were negatively correlated with the Fuhrman grade of tumors. Significant differences were observed in high- and low-grade CCRCC among ADCf(p<0.001), ADCs(p=0.005), and f value (p<0.001). When differentiating Fuhrman low- from high-grade tumors, the ADCf revealed a area under ROC curve (AUC) of 0.959, which was higher than ADC value (0.789)(p=0.046), while the ADCs (0.807) and f ( 0.833) showed no significantly difference from ADC(p=0.85 for ADCs, p=0.73 for f). Conclusion Biexponential DWI provide additional parameters for CCRCC, and ADCf is more accurate compared to ADC value in characterizing Fuhrman grade of CCRCC.