Objective To analyze the effect of intravenous dripping of 3% sodium chloride solution on prevention of diluted hyponatremia during transurethral vaporization of the prostate (TUVP). Methods Eighty-five cases with benign prostatic hyperplasia (BPH) accompanied with typical lower urinary tract symptoms (LUTS) were divided into two groups during undergoing TUVP operation: the control group(n=38) given Ringer's solution dripping (3ml/min) and the concentrated sodium chloride injection group(n= 47) given 3% sodium chloride solution dripping (2～4ml/min). All of the operations were taken via Wolf electric resection system, and the operation time was≥60 min. The complete blood count and serum electrolyte were determined before operation and 60 minutes after operation beginning, and the data were compared between the two groups. Results The decrease amplitude of serum sodium was obviously smaller in concentrated sodium chloride injection group[(1.45±5.14)mmol/L] than that in the control group[(7.79±6.64) mmol/L] 60 minutes after operation beginning (P<0.05). Conclusions Giving 3% sodium chloride solution by intravenous drip during TUVP may reduce the severity of diluted hyponatremia and postpone the occurrence of hyponatremia, and thereby decrease the risk of transurethral resection syndrome.