Objective: The inhibitory effects of phenyllactic acid on Enterobacter hormaechei and its biofilm was explored. Method: The inhibitory effect of PLA on E. hormaechei and its biofilm was assessed through various experimental techniques， including measurement of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)， growth curve， flow cytometry， alkaline phosphatase (AKP) activity， cell membrane integrity， DNA content， motility test， biofilm formation and confocal laser scanning microscopy observation. Results: The MIC and MBC of PLA to E. hormaechei was 1.25 mg/mL and 2.5 mg/mL， respectively， which could completely inhibit the growth of E. hormaechei. Flow cytometry results showed that 1/2 MIC and MIC phenyllactic acid could not cause apoptosis and necrosis， while 2 MIC PLA could cause cell death. The lag phase of growth curve of E. hormaechei cultured at 28 ℃ was nearly 1 h longer than that at 37 ℃， but the maximum biomass of E. hormaechei was not affected， and the apoptosis rate was not significantly different. PLA damaged the structural integrity of cells， resulting in decreased intracellular AKP activity and leakage of nucleic acids and proteins. 2 MIC PLA could significantly reduce the content of bacterial DNA. PLA treatment resulted in decreased motor capacity and biofilm production of E. hormaechei. Conclusion: PLA had a strong inhibitory effect on E. hormaechei and its biofilm.