Abstract: Compared with traditional small molecule drugs, peptides have advantages such as higher biological activity, stronger target specificity, and fewer adverse effect, and are increasingly attracting the attention of new drug researchers. Due to their poor permeability and stability, and poor oral absorption, most peptide drugs are administered through non-gastrointestinal routes, which leads to poor patient compliance. Therefore, the development of oral peptide formulations has great application value but also faces huge challenges. This article reviews the absorption barriers faced by oral peptides, proposes general strategies for oral delivery in response to these barriers, and lists successful cases of oral peptides. The main absorption barriers faced by oral peptides include chemical barriers, enzyme barriers, mucus layer barriers, epithelial cell barriers, and the influence of individual biological differences. Strategies to improve oral absorption mainly include chemical modification to change the structure of peptides, inhibition of intestinal enzyme degradation, osmotic promotion technology, self-emulsifying/nano-delivery technology, etc. These technologies are all aimed at protecting the stability of peptides and enhancing their transmembrane absorption, which has greatly improved the oral absorption of peptide drugs. This article also takes semaglutide and octreotide as examples to deeply analyze the mechanism of oral delivery of peptide drugs, providing theoretical support for improving the oral absorption of peptide drugs and realizing the research on oral delivery of peptide drugs.