Postmenopausal osteoporosis is one of the most prevalent skeletal disorders in women and is featured by the imbalance between intraosseous vascularization and bone metabolism. In this study, a pH‐responsive shell–core structured micro/nano‐hydrogel microspheres loaded with polyhedral oligomeric silsesquioxane (POSS) using gas microfluidics and ionic cross‐linking technology are developed. This micro/nano‐hydrogel microsphere system (PDAP@Alg/Cs) can achieve oral delivery, intragastric protection, intestinal slow/controlled release, active targeting to bone tissue, and thus negatively affecting intraosseous angiogenesis and osteoclastogenesis. According to biodistribution data, PDAP@Alg/Cs can successfully enhance drug intestinal absorption and bioavailability through intestine adhesion and bone targeting after oral administration. In vitro and in vivo experiments reveal that PDAP@Alg/Cs promoted type H vessel formation and inhibited bone resorption, effectively mitigating bone loss by activating HIF‐1α/VEGF signaling pathway and promoting heme oxygenase‐1 (HO‐1) expression. In conclusion, this novel oral micro/nano‐hydrogel microsphere system can simultaneously accelerate intraosseous vascularization and decrease bone resorption, offering a brand‐new approach to prevent postmenopausal osteoporosis.