The antibacterial mechanism of sodium lactate(NaL) to Pseudomonas aeruginosa was studied in this paper.Two aspects were designed as the following: the structural integrity of bacterial cell membrane(wall) and the synthesis of ATP in bacteria.The results showed that the structural integrity of bacterial cell membrane was much more significantly destroyed by 0.02 g/mL NaL than control(P<0.05).Meanwhile,ATP product of the treatment with 2 g/100mL NaL was less than that of the control.The conclusion of experiment provides some theoretical references for using NaL as right and effective new food preservatives.