Objective To evaluate the role of multi-drug efflux pumps system involved in the resistance of pan-time pseudomonas aeruginosas to antibiotics.Methods Established SYBR-Green I real-time RT-PCR method was employed to quantify the mRNA levels of MexAB-OprM,MexCD-OprJ,MexEF-OprN,MexXY-OpM and the differences of mRNA levels between pan-resistant P.aeruginosas and susceptible p.aeruginosas were compared.Results The mRNA levels of MexAB-OprM,MexCD-OprJ,MexEF-OprN,MexXY-OprM in pan-resistant P.aeruginosas were higher than those in susceptible P.aeruginosas(P<0.01).The percentage of overexpression was 18.9% in MexAB-OprM,13.5% in MexCD-OprJ,56.8% in MexEF-OprN and 35.1% in MexXY-OprM respectively when the cutoff value was defined as four times of the mean value of susceptible P.aeruginosas.Conclusion The efflux pump system may play a key role in the resistance of pan-resistant Pseudomonas aeruginosas to antibiotics.