Abstract: This study aimed to construct a DC-targeted aptamer-modified Pseudomonas aeruginosa(PA)DNA vaccine delivery system. The cationic liposome was prepared by ethanol injection method. The cationic liposome loading pVAX1-OprF-VP22(Lip-pOprF-VP22)was prepared by electrostatic adsorption method. The encapsulation efficiency of Lip-pOprF-VP22 with different mass ratios of DOTAP/pDNA on pVAX1-OprF-VP22, cytotoxicity and transfection rate to DC2. 4 in vitro were discussed. The particle size and zeta potential of Lip-pOprF-VP22 with best mass ratio were tested. Aptamer-modified cationic liposome loading pVAX1-OprF-VP22(Apt-Lip-pOprF-VP22)was prepared by post-insertion method. The expression of OprF protein after transfection of DC2. 4 and its effect on the maturation of bone marrow-derived dendritic cells(BMDCs)were detected. Data showed that as the mass ratio of DOTAP/pDNA increased, the encapsulation efficiency of Lip-pOprF-VP22 on pVAX1-OprF-VP22 was gradually increased. When the mass ratio was 5 ∶1, pVAX1-OprF-VP22 was encapsulated well. When Lip-pOprF-VP22 with different mass ratios was applied to DC2. 4 for 24 h or 48 h, the survival rates of DC2. 4 were all above 80%. When the mass ratio of DOTAP/pDNA increased from 2 ∶1 to 10 ∶1, the transfection rate increased first and then decreased. When the mass ratios of DOTAP/pDNA were 4 ∶1 and 5 ∶1, the transfection rates were relatively high. When the mass ratio of DOTAP/pDNA was 5 ∶1, the particle size of Lip-pOprF-VP22 was(171. 67±1. 27)nm, and the Zeta potential was(11. 30±0. 57)mV. Furthermore, Apt-Lip-pOprF-VP22 can express more OprF protein and significantly promote the maturation of BMDCs. In conclusion, Apt-Lip-pOprF-VP22 can target to DC and promote the maturation of DC.