OBJECTIVE： To establish a method for the concentration determination of tazobactam sodium in human urine， and to study urinary excretion pharmacokinetics. METHODS： The urine samples were extracted by 10％ perchloric acid， and then determined by LC-MS/MS. The separation was performed on a Hypersil GOLD C18 column with mobile phase consisted of ethanol-water （30 ∶ 70，V/V） at flow rate of 0.2 ml/min； the column temperature was set at 30 ℃， and sample size was 5 μl. ESI was used， and positive ion scanning was conducted in MRM mode； ion pair for quantitative analysis was m/z 301→168. 8 healthy volunteers were given Cefotaxime sodium and tazobactam sodium for injection （6 ∶ 1，m/m） 2.34 g intravenously， and then urine samples were collected before medication， 0-2， 2-5， 5-8， 8-12 and 12-16 h after medication.  RESULTS： The linear range of tazobactam sodium was 0.25-500 μg/ml （r＝0.999 9）. The limit of quantitation was 0.25 μg/ml； RSDs of inter-batch and intra-batch were all lower than 10％； method recoveries were 93.8％-111.8％； extraction recoveries were 93.9％-99.7％； medium effect ranged 87.6％-107.2％. 16 h after medication， accumulative excretion amount of tazobactam sodium in urine was （209.70±39.24） mg and accumulative excretion rate was （61.7±11.5）％. CONCLUSIONS： LC-MS/MS method can be used for the concentration determination of tazobactam sodium in human urine and excretion kinetics study. It is simple， rapid and sensitivity； tazobactam sodium mainly excrete viareral tissue.