Objective To construct the recombinant plasmid of PA-ⅠL and express in E.coli BL 21 (DE3), and evaluate the biological activity of recombinant protein.Methods PA-ⅠL gene was amplified by PCR using primers designed according to Pseudomonas aeruginosa genome sequences and then cloned to the vector pET -28a ( +).The recombinant plasmid was transformed into E.coli BL21(DE3) and induced to express by IPTG.The recombinant protein was purified by nickel affinity chromatography.The binding activity of recombinant PA-ⅠL with Gb3/CD77 was evaluated by flow cytometry.The function of recombinant PA-ⅠL on the binding of bacteria with host cells was evaluated by colony plate counting.Results and Conclusion The recombinant PA-ⅠL protein was highly expressed in E.coli BL21(DE3) and protein purity by SDS-PAGE analysis was high after nickel affinity chromatography .Besides, the recombinant PA-ⅠL had binding activity to Gb3/CD77 and inhibited the binding of PAO1 to host cells in a dose-dependent manner.