Abstract: The ferric uptake regulator (Fur) is an important regulation factor in bacteria. To explore the effect of fur gene on iron uptake and biofilm formation ability of Klebsiella pneumonia, and analyze the regulatory effect of Fur on the possible target gene fyuA (receptor for Yersinia), the unmarked fur-deletion mutant and complementation strain C-Δfur were constructed through homologous recombination. Phenotype of wild strains, mutant strains and replenishment strains was determined by growth curve, CAS detection and crystal violet staining, and the transcription regulation mechanism of Fur on fyuART-q was clarified by PCR and GFP fusion assay. The results showed that fur affected the growth rate of bacteria; Deletion of the fur gene increased the production of siderophores and reduced the biofilm formation; The fyuA gene was negatively regulated by Fur under iron sufficient conditions.