To compare the diagnostic efficiency of IVIM parameters and conventional DWI (b=600 and b=990) derived from 3D whole-lesion (W-L ROI) delineation. Forty-three patients with 46 pathologically confirmed thyroid nodules were involved. According to ROC curve, D, f, ADC600 and ADC990 values showed diagnostic significance with the AUC values of 0.962, 0.756, 0.970 and 0.939 respectively. Furthermore, the Youden index of D value (0.871) was higher than that of ADC600 (0.826). IVIM is a more promising tool in the differentiation of benign and malignant thyroid nodules using W-L ROI delineation than conventional DWI.