Objective To explore the preoperative guiding value of intravoxel incoherentmotion diffusion weighted imaging (IVIM-DWI) in rectal cancer patients. Methods 60 patients with rectal cancer were selected and their preoperative imaging data were obtained. The standard ADC value (ADC), slow diffusion ADC value (D), fast diffusion ADC value (D* ) and perfusion related volume (f) and other parameters were measured and compared in the rectal cancer masses and normal rectal tissues and in the different TNM stages and different degrees of tissue differentiation. Results The ADC and D values in the rectal cancer masses were significantly lower than those in the normal rectal wall (P<0.05), and the D* value was significantly higher than that in the normal rectal tissues (P<0.05). However, there was no significant difference in F value between the two tissues (P>0.05). With the increase of TNM stages, the D value was decreased gradually (P<0.05), but there was no significant difference in the values of ADC, D* and f among different stages (P>0.05). With the increase of differentiation degree, the values of ADC and D were increased gradually, but there was no significant difference in the ADC value between the high differentiation and moderate differentiation (P>0.05), and the ADC value of moderate and poor differentiation was significantly different (P<0.05), and there were significant differences in the D value between the among two group of the three group (P<0.05). There was no significant difference in the values of D* and f among the three groups (P>0.05). Conclusion The ADC, D, D* , f and other parameters provided by IVIM imaging can reflect the pathophysiological state of tumor tissues, especially the ADC and D* values are of important value for preoperative evaluation of stages and differentiation degree of rectal cancer.