Hyaluronan (HA) molecules are long, unbranched chains of variable length that consist of repeating disaccharide subunit of D-glucuronic acid (b1->3) and N-acetyl-D-glucosamine (b1->4). Owing to its stable properties and high viscosity, hyaluronic acid that derivatives are widely used in food, cosmetics, and pharmaceutical industries. However, the role of HA in probiotics was not known while the probiotics are used very commonly and the number of probiotics are usually lower than the number in label. Therefore, to understand the HA function clearly and look for the activity on probiotics, the research about the effect of HA on the the morphological and physiological differentiation of Lactobacillus was performed. The examination tests were performed by using the light microscope, scanning electron microscope. The bacteriocin tests were done by agar diffusion test. In order to looking for the survival, the colony counting was done. Besides, the experiment used the API 50 CHL kit (BioMerieux) to do biochemical test and identify the strain after treated with hyaluronic acid. The result showed the effects of HA on Lactobacillus in the shape changing, cell growth, bacteriocin production but not effect on the biochemical tests. Even there was the changing in shape, cell growth, bacteriocin production, the experimental L. acidophilus LA1 was still such identified by using API 50 CHL kit (BioMerieux).