Probiotics and bovine colostrums had been proven to be beneficial for human health. Lactobacillus rhamnosus ZDY114 and anti-Helicobacter pylori bovine colostrums were used for the preparation of microecological additives, and their synergistic antidigestion effect in the simulated gastrointestinal tract (in vitro) was investigated. Either L. rhamnosus or purified IgG from immune colostrums was very sensitive in simulated gastric environment and slightly sensitive in simulated intestinal tract. No viable counts were recovered from the solution of dissolved freeze-dried powder (7.14 log(10) CFU/ml) of L. rhamnosus when digested at pH 3.0 with pepsin for 30 min. Activity of purified IgGs from immune colostrums could not be detected when digested at pH 3.0 with pepsin for 30 min; 29% titer could be detected when digested at pH 8.0 with trypsin for 5 h. The IgGs in nonpurified immune colostrums presented stronger resistance against gastrointestinal digestion than purified IgGs. Moreover, the combination of L. rhamnosus ZDY114 and immune colostrums strengthened their antidigestion ability. Even under pH 3.0, 4.0 with pepsin, the titer of anti-HP IgG maintained above 123 and 83.3%, respectively. Similarly, that titer was above 93.3% when digested at pH 8.0 with trypsin for 4.5 h. In conclusion, L. rhamnosus and anti-Helicobacter pylori bovine colostrums had synergistic antidigestion effect in simulated gastrointestinal tract (in vitro).