OBJECTIVE：To provide reference for clinical rational use of piperacillin sulbactam for the anti-infection of Pseudomonas aeruginosa. METHODS： 105 inpatients with normal liver and kidney functions that the pathogen was diagnosed as P. aeruginosa and susceptible to PIP/SBT from Jul. 2013 to Jun. 2014 were chose， dosing regimens were collected， the minimum inhibitory concentration （MIC） of piperacillin sulbactam for P. aeruginosa was 1 mg/L based on a one compartment pharmacokinetic mode， the standard value of the percentage of the duration of plasma concentration more than MIC （T＞MIC） to dosing interval time was 45％，T＞MIC was calculated with pharmacokinetic formula of both single dose and multiple dose repeated intravenous administration to analyze the situation of reaching the standard of T＞MIC； and the dosing interval time of the original scheme was prolonged appropriately to investigate the situation of reaching the standard of the percentage of （T＞MIC） to dosing interval time. RESULTS： 47 patients’dosing regimens were given 3.0 g PIP/SBT once every 8 hours， and the others were given 3.0 g PIP/SBT once every 12 hours； for P. aeruginosa， the percentages of T＞MIC to dosing interval time were respectively 99.93％ and 73.13％ with pharmacokinetic formula of single dose intravenous administration， and 99.98％ and 68.08％ with pharmacokinetic formula of multiple dose repeated intravenous administration； and the percentages of the interval time prolonged to 16 h were respectively 54.84％ and 51.06％， both reached the standard value. CONCLUSIONS： Quantitative analysis of PK/PD prediction parameters can be used to evaluate and optimize the clinical dosing regimens and guide the clinical practice.