Purpose To quantitatively analyze the blood perfusion parameters after kidney transplantation with acute and chronic rejection by using contrast-enhanced ultrasonography (CEUS), in order to provide rapid assessment for rejection prognosis. Materials and Methods Thirty-one patients with kidney transplantation were followed up and divided into three groups according to clinical symptoms and graft biopsy results:normal group (n=6), acute rejection group (n=12) and chronic rejection group (n=13). CEUS was carried out to assess renal microcirculation perfusion. Results CEUS showed that the normal renal parenchyma was enhanced homogeneously whilst the rejected parenchyma was enhanced heterogeneously. The differences of area under the curve among the three groups was statistically signiifcant (F=37.102, P<0.01), with normal group >chronic rejection group > acute rejection group. The peak intensity in normal group was higher than that in acute rejection group (P<0.01), but it showed no difference with that in chronic group. In acute and chronic rejection groups, the arrival time and the time to peak intensity in interlobar artery and cortex were all later than those in normal group (P<0.05). The ascending slope of TIC in segmental artery, interlobar artery and cortex in the two rejection groups was both signiifcantly less than that in normal group. Conclusion CEUS is a valuable diagnostic tool in the evaluation of microcirculation perfusion in kidney graft, and can provide important reference for the prognosis of acute and chronic rejection after kidney transplantation.