Abstract: The mycelia morphology of Lactobacillus acidophilus cultured at pH values of 1.5, 3.5 and 6.2 were observed with Scanning electron microscope (SEM) . The result of scanning electron microscope showed that the mycelia morphology of Lactobacillus acidophilus ind-1 was typical rhapidosome without flagella and capsular, and the thallus arranged with a single or germination and had no branch. What’s more, the mycelia morphology of Lactobacillus acidophilus ind-1 differed from each other at different pH values. At pH of 1.5, the mycelia morphology of Lactobacillus acidophilus ind-1 was short rod with rounded ends and thickset thallus.But at pH of 6.2, the mycelia morphology was long rod with slender thallus. Through comparison, it was found that the mycelia morphology of Lactobacillus acidophilus ind-1 changed from long rod to short rod, and the thallus changed from slender to thickset followed with the decrease of pH values.