Objective： To investigate the role of Notch1／Jagged1 activation pathway in the development of renal tubulointerstitial fibrosis in vivo. Methods： Rats were sacrificed after1 day， 3 days， 7 days and 14 days of ureteral obstruction（UUO）， and sham-operated rats were sacrificed as the control. Notch1／Jagged1 mRNA and protein and Fibronectin （FN） were analyzed with semi-quantitative RT-PCR and western blot. Results： Notch1／Jagged1， FN mRNA and protein levels of the UUO group at the 1st， 3rd， 7th， 14th days in the kidneys of rats with obstructed kidneys， were significantly increased （P < 0.05 or P < 0.01）， compared to sham-operated rats. Notch1／Jagged1 mRNA expression were peaked 7 days after UUO （P < 0.05）. Jagged1 protein expression was peaked 1 day after UUO. The levels of Notch1 and FN protein expression were peaked 14 days after UUO（P < 0.05）. Conclusion： Expressions of Notch1／Jagged1 are increased in renal tissue after UUO. Notch1／Jagged1 signaling pathway may be involved in UUO rats and plays a concordant role in the pathogenesis of renal interstitial fibrosis.