As a vital component of blood, platelets play crucial roles in hemostasis and maintaining vascular integrity, and actively participate in inflammation and immune regulation. The unique biological properties of natural platelets have enabled their utilization as drug delivery vehicles. The advancement and integration of various techniques, including biological, chemical, and physicochemical methods, have enabled the preparation of engineered platelets. Platelets can serve as drug delivery platforms combined with immunotherapy and chemokine therapy to enhance their therapeutic impact. This review focuses on the recent advancements in the application of unactivated platelets for drug delivery. The construction strategies of engineered platelets are comprehensively summarized, encompassing internal loading, surface modification, and genetic engineering techniques. Engineered platelets hold vast potential for treating cardiovascular diseases, cancers, and infectious diseases. Furthermore, the challenges and potential considerations in creating engineered platelets with natural activity are discussed.