Abstract: Objective To investigate the ¹³¹I-orthoiodohippurate renography with hydronephrosis and renal function,in order to further clarify the clinical diagnosis and treatment of hydronephrosis and provide a reliable basis.Methods Retrospective analysis the results of ¹³¹I-ortboiodohippurate renography in 120patients whose urology inpatients.In accordance with the side of hydronephrosis,bilateral hydronephrosis and light,moderate and severe packet.The features of renography and the changes of functional parameter values in each group was analysised.And compared with the results of clinical evaluation about renal function and blood urea nitrogen(BUN),creatinine(Cr)levels.SPSS.16 statistical software was used for statistical analysis.Results The incidence of abnormal renal funetion in varying degrees of hydronephrosis were significantly higher than those without hydronephrosis(98.9% vs.39.3%,χ₂=87.492,P<0.001).Presenting mainly high level and extension line and continued to inerease for the type of renography in mild to moderate degree hydronephrosis groups.Severe hydronephrosis is presenting mainly such as the low level and extension line for the type of renography.Varying degrees of hydronephrosis different have meant that the residual rate of increase of 15 minutes,both of the Enrichment rate and renal index(RI)is lower(F=74.56,20.0,61.917,P<0.001).The incidence of Renal insufficiency in the group of bilateral hydronephrosis was significantly higher than the unilateral hydronephrosis(55% vs 11%,χ₂=13.848,P<0.001).And the extent of severe renal insuflciency,serum BUN and Cr levels were significantly higher than the group of unilateral hydronephrosis(F=13.671,24.302,P<0.001).The average of the functional parameters that both sides of renography there is a certain degree of correlation with BUN,Cr in the unilateral hydronephrosis group.Conclusion The ¹³¹I-orthoiodohippurate renography there is a higher sensitivity on the assessment of hydronephrosis and renal function,but lack of specificity.The analysis should be combination with clinical situation.