In order to study the effect of alginate lyase (AlgL) on biofilm and bacterial factors RpoS gene of hypervirulent Klebsilla pneumoniae (HvKP), 30 strains of Klebsiella pneumoniae (KP) were isolated from clinical samples. They were identified by automatic rapid microbial mass spectrometry detection system VITEK, were done susceptibility tests for drug resistance analysis, the strains with positive wire drawing test were identified as HvKP. The bacterial biofilm was detected by semi quantitative crystal violet staining. The expression of RpoS gene was detected by polymerase chain reaction (PCR). AlgL can significantly inhibit HvKP biofilm, and the thickness of biofilm is positively correlated with the expression of RpoS gene, indicating that alginate lyase can inhibit the formation of HvKP biofilm. It provides a research basis for AlgL in the clinical treatment of HvKP.