Abstract <p>One of the main treatment methods for diabetes is the subcutaneous injection of insulin. However, frequent subcutaneous injections can lead to adverse reactions, such as swelling and inflammation at the injection site, resulting in poor patient compliance. In contrast, non-invasive insulin delivery methods, particularly oral administration, offer advantages in terms of improved patient compliance, convenience, and cost-effectiveness. Nevertheless, the multiple physiological barriers in the gastrointestinal tract pose significant challenges to the oral delivery of protein or peptide drugs. Biodegradable polymer materials are now widely used in the research of oral insulin delivery due to their excellent properties, including good biocompatibility, biodegradability, and low toxicity. These materials are capable of protecting insulin from degradation in the harsh environments of the stomach and intestinal lumen, thus enhancing the oral bioavailability of insulin. This paper has described the various physiological barriers of oral insulin delivery and summarized the types and properties of biodegradable polymeric materials that have been used for oral insulin delivery in recent years.</p>