Ferrichrome is a kind of high-affinity iron(III) chelators and its complex with Fe3+ can be specifically recognized by the corresponding receptors located on the outer membrane of some bacterial cells. Quantum dots as a type of semiconductor nanocrystals have high luminance and good resistance to photobleaching. Herein, ferrichrome was conjugated with polyethylene glycol-phosphoethanolamine-coated quantum dots to produce a new type of quantum dot-ferrichrome bioprobes. The quantum dot-ferrichrome bioprobes were used for recognizing Pseudomonas fluorescens (P. fluorescens) isolated from Dong-Hu Lake in China. P. fluorescens could be recognized quickly and sensitively with quantum dot-ferrichrome bioprobes by forming cell clusters through reaction between ferrichrome-ferric complex and its receptors. It was multiple ligands on a quantum dot and multiple receptors on a P. fluorescens cell that made the bacteria cluster. Single cells can also be realized with superfluous quantum dot-ferrichrome bioprobes to occupy the receptors on bacterial outer membrane. The biosensitive quantum dot-ferrichrome kept excellent fluorescent property of quantum dot and might be a promising bioprobes for fluorescent Pseudomonads targeting.