The intestinal adhesion of probiotics is the key factor for long-term intestinal colonization. In order to increase the intestinal adhesion of exogenous probiotics, the sulfhydryl Codonopsis pilosula polysaccharide (sC-CPP-2) was prepared by two-step chemical modification of carboxymethylation and thiolation of the Codonopsis pilosula polysaccharide (CPP-2) isolated previously. Adhesion effect of intestinal mucus on Lactobacillus rhamnosus GG (LGG) with the addition of sC-CPP-2 was analyzed by in vitro adhesion test and laser confocal microscopy. The adhesion of sC-CPP-2 to LGG was indirectly verified by the composite film formed by Codonopsis pilosula polysaccharide and its modified components and sodium alginate. The interaction between sC-CPP-2 and intestinal mucus was detected by rheometer and classical tensile test. The results showed that the substitution degree of carboxymethyl Codonopsis pilosula polysaccharide (C-CPP-2) was 0.588±0.026, and the sulfhydryl content in sC-CPP-2 was (279.50±5.97) μmol/g. After thiolation modification, C-CPP-2 was in the coexistence of sulfhydryl and carboxyl groups. The thiol group on the surface of sC-CPP-2 could form disulfide bonds with the cysteine on the surface protein of LGG, which increased the intestinal adhesion of LGG. The maximum separation force between sC-CPP-2 and intestinal mucus was (101.82±5.78) mN, and the total adhesion work was (120.07±6.81) μJ. Interaction between sC-CPP-2 and intestinal mucus was enhanced, the apparent viscosity was increased, and the adhesion was significantly enhanced. It was confirmed that sC-CPP-2 could play a mediating role in connecting LGG and intestinal mucus, and enhance the intestinal adhesion of LGG, hoping to provide reference for improving the adhesion and colonization of probiotics in intestine.