Abstract: Objective To research the degression of renal function of ⁹⁹Tc^m-diethylene triamine pentaaceticacid(⁹⁹Tc^m-DTPA) renal imaging in rabbits with acute upper urinary tract obstruction and its early recovery after relief. Methods Twenty-four health rabbit models with left acute upper urinary tract obstruction were built up. ⁹⁹Tc^m-DTPA renal imaging was performed before making model and after obstruction 1, 3, 5-7 and more than 8 weeks respectively and 4 weeks after relief of obstruction. Results After obstnrction 1 and 3 weeks, ⁹⁹Tc^m-DTPA imaging showed development in left renal. Values of glomerular filtration rate(GPH) and uptake ratio decreased, while time to rcach the peak increased. These are obviusly different compared with those before obstruction(t=2.916, t=7.034, P<0.01). Affer obstruction 5-7 weeks, ⁹⁹Tc^m-DTPA imagingshowed cortex developert. Values of GFR and uptake ratio decreased obvious, while time to reach the peak increased obviously. These are obviously different cempaved with those before obstruction(t=6.722, t=7.470, t=3.678, P<0.01). Affer obstruction more than 8 weeks, ⁹⁹Tc^m-DTPA imaging showed no obvious development. In those rabbits with durations of 1-3 weeks obstructions, the renal function could almost recover within 4 weeks after relief of obstruction. GRF is 31.23±14.4(t=2.627, P<0.05), uptake ratio is 4.09±2.10(t=2.795, P<0.05). The time to reack the peak showed no obvious diflerence(t=1.435, P>0.05). With obstruction of 5-7 weeks, the GRF and uptake ratio, could recover partly to some extent. But with obstruction for more than 8 weeks, the renal function could not recover. Conclusions For the acute upper urinary tract obstruction, the renal function is most remarkable decreased in the early time, and can be restored after relief. For long time obstruction, even if relieved, the renal function is not easily to restore. The dynamic renal imaging can reflect the extent of the renal damage and its recovery, and could be used as a reliable indicator.