Objective To analyze the influencing factors of affected renal function after laparoscopic nephron-sparing nephrectomy with segmental renal artery blocking (SRPN) for low R.E.N.A.L.score small localized renal tumor with follow-up data.Methods The data of 33 patients was collected,who underwent SRPN for small renal tumor from January 2010 to April 2012,and were followed-up for 5 years successfully.In 33 integrated data of 5-year follow-up,there were 14 males and 19 females,aged(56.5 ± 11.8)years.The preoperative affected renal glomerular filtration rate (aGFRpre),postoperative affected renal glomerular filtration rate (aGFRpost),the residual ratio of aGFR (aGFRpost/aGFRpre),preoperative affected renal volume (aVolpre),postoperative affected renal volume (aVolpost) and the residual ratio of aVol (aVolpost/aVolpre) were collected at the postoperative 3rd,6th,12th,24th and 60th month in follow-up period.Preoperative and postoperative data were analyzed by paired-sample T test.Multivariate linear regression analysis determined the influence of body mass index,operation time,localized warm ischemia time and distance from tumor to renal collecting system.Compare the correlation between aGFRpost/aGFRpre and aVolpost/aVolpre.Results All 33 cases were performed successfully.The mean operation time was (108.4 ± 9.1) min,and the mean time of segmental renal artery blocking was (23.3 ± 3.0) min.Postoperative pathologic 17 (51.5％) of clear cell carcinoma,5 (15.2％) of papillary carcinoma,3 (9.1％) of chromophobe cell carcinoma.All of above margins were negative.8 (24.2％) of angiomyolipoma (9.1％).All 33 cases were followed up for more than 5 years.The 5-year overoll survival (OS) and cancer specific survival (CSS) were 100％.In the 3rd,6th,12th,24th and 60th month,aGFRpost were (34.6 ± 4.6) ml/min,(34.7 ± 4.8) ml/min,(34.9 ± 4.4) ml/min,(35.1 ± 4.4) ml/min,(35.2 ± 4.2) ml/min,decreased of (10.4 ± 2.4) ml/min,(10.4 ± 2.6) ml/min,(10.1 ± 2.4) ml/min,(9.9 ± 2.4) ml/min,(9.8 ± 2.5) ml/min compared with aGFRpre (P ＜ 0.05).Multivariate linear regression analysis showed that body mass index,operation time,localized warm ischemia time in SRPN and distance from tumor to renal collecting system were unable to influence aGFRpost (P ＞ 0.05).The correlation coefficients between aGFRpost/aGFRpre and aVolpost/aVolpre were 0.659,0.667,0.663,0.629,0.604 respectively,and the difference was statistically significant (P ＜ 0.05).Conclusions For low R.E.N.A.L.score small localized renal tumor with SRPN,the decrease of postoperative affected renal function is relevant to postoperative affected renal volume,not as to operation time,localized warm ischemia time in SRPN and distance from tumor to renal collecting system.