Probiotics have many physiological functions， especially in the maintenance of human intestinal health. However， it also has the limitation of being vulnerable to the influence of external environment and gastric environment. Therefore， it has become a research hotspot to find new substances which are harmless to human body and can promote the proliferation and tolerance of probiotics. Therefore， Lactobacillus acidophilus was taken as the research object to explore the beneficial effect of whey protein hydrolysate on Lactobacillus acidophilus JC1. The whey protein hydrolysate was added to the liquid medium of L. acidophilus JC1， and the change of the number of living bacteria was measured regularly， and the bacterial growth was described by the kinetic equation of microbial growth. In addition， the utilization of L. acidophilus JC1 to whey protein hydrolysate was determined， and the effects of WPH on biofilm and extracellular polymeric substances（EPS） were explored. The results showed that with the increase of the amount of whey protein hydrolysate， the growth promoting effect was strengthened， and the lag phase of bacteria was shortened and the logarithmic period was entered ahead of time. The content of bacterial biofilm and EPS increased significantly with the addition of whey protein hydrolysate. The beneficial effect of whey protein hydrolysate was likely to be that it enhanced the quorum sensing system of L. acidophilus JC1， thus promoting the ability of bacteria to resist the adverse environmental impact and promoting the growth and reproduction of bacteria.