Probiotics are highly valued in basic research， industrial transformation and clinical medicine for their effectiveness in maintaining intestinal health， regulating immunity and preventing and/or treating chronic diseases in humans. Benefiting from the increasing public awareness of probiotics， their products have become popular in daily consumption scenarios. Fermented dairy products， as an important product form for probiotics to exert health effects， have important application value because they combine the probiotic effect of strains with the health effects of dairy products. This paper took Lacticaseibacillus casei Zhang， a probiotic strain with far-reaching influence in both scientific evidence and industrial translation， as an example， and focused on its known probiotic properties and application in fermented dairy products to provide a theoretical basis for the subsequent in-depth analysis of the functional properties of this strain.