The invention discloses an oral vaccine delivery system. W1 of W1 / O / W2 type nanoparticles is a vaccine medicine phase, an organic phase O is selected from PLGA and HP55, an external water phase W2 and a continuous water phase are selected from poloxamer 188, and a vaccine medicine is a double epitope-double adjuvant helicobacter pylori vaccine. The method adopts a polymer material having good biological safety and good compatibility to prepare the nanoparticles, a preparation process and a formula are optimized, the oral vaccine delivery system is non-toxic, free of any side effects, easy to manufacture and low in cost. In the field of biological medicines, the nanoparticles can be used for oral taking of a helicobacter pylori subunit vaccine, accordingly helicobacter pylori infection related diseases are prevented and treated, and huge economic benefits and social benefits are brought.