Lactobacilli have the probiotic effects of regulating gastrointestinal microbiota and improving gastrointestinal function. Helicobacter pylori (Hp) is a gram-negative pathogen colonizing in gastric mucosa and can induce gastric cancer, while the eradication rate of Hp is decreasing year by year. In recent years, Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus gasseri and other Lactobacilli combined with antibiotics are applied to treat Hp infection. However, results of various clinical studies are inconsistent, and the eradication rate of Hp still needs to be improved. This article reviews the clinical researches about the effects of Lactobacilli on the eradication of Hp, and further discusses the molecular mechanisms of Lactobacilli against Hp infection including direct killing effects of bacteriocin, adhesion inhibition, gastrointestinal microbiota regulation and inflammation inhibition, aiming to provide a new approach for screening optimal Lactobacilli strains and therefore to improve the clinical therapeutic effect of Hp infection.