Abstract: Objective To investigate the alteration of calcineurin （CaN） activity in vital tissues and organs in the renal vascular hypertensive rats（RHR）. Methods The models of renal vascalar hypertensive rats were established by the operation of “one-kidney one-clip”. Thirteen Wistar rats were divided into two groups randomly: operation groups（RHR,n =7） and sham operation groups（control,n =6）. CaN activity was measured in various tissues and organs by using PNPP as substrate 4 weeks after operation. By using immunohistochemical staining methods,the distribution of CaNA β in cardiac myocytes was examined. Results Compared with controls,CaN activity in heart,spleen,kidney,lung,brain of RHRs was increased by 175%,90%,84%,57%,43%,respectively（ P ＜0.05）,while in liver was decreased by 27%（ P ＜0.05）. In immunohistochemical staining study,there was an increase of postive brown immunostaining of CaNA β in myocardial cytoplasmic of RHRs. Conclusion CaN activity in heart,spleen,kidney,lung,brain,liver underwent remarkable changes in RHRs. The maximum increase of CaN activity was found in heart. Upregulated expression of immunostaining of CaNA β in myocardial cytoplasmic was found in of RHRs,suggesting its role in cardiomyocyte remodeling.