It has been more than 20 years since the first intracoronary stent was placed by Jacques Puel and Ulrich Sigwart in Toulouse, France, in 1986, and is now widely used in the treatment of coronary artery disease. Throughout the development of coronary stents, it can be divided into the era of bare stents and the era of drug-eluting stents. Advantages of bare stent (BMS): 1. Its efficacy and safety are better than PTCA alone; 2. It can reduce the restenosis rate after PTCA (from 30-50% to 20-30%); 3. Postoperative aspirin and thienopyridine dual antiplatelet therapy is shorter than drug stent (DES), at least 1 month, preferably 12 months (if the patient has a high risk of bleeding, apply at least 2 weeks). Disadvantage: postoperative in-stent restenosis due to endothelial hyperplasia leads to a high rate of revascularization. DES, on the other hand, significantly inhibits intimal hyperplasia, thereby greatly reducing the rate of restenosis and revascularization after stenting (5-10%). Existing studies have shown that DES has better efficacy than BMS and at least comparable safety to BMS. There are various ways to classify coronary stents: according to the design structure of stents, they can be divided into mesh, tubular, ring and winding stents (tubular and ring stents are more commonly used in clinical applications). According to the different materials of stents, they can be divided into 316L stainless steel, cobalt-chromium alloy, nickel-titanium, tantalum and other stents. According to the different delivery methods, they are divided into balloon-expandable stents and self-expandable stents. Different stents are designed according to special applications, such as stents suitable for bifurcation lesions and stents with membranes for coronary aneurysms or perforations. DES are the most widely used in clinical practice and are constantly being updated. The first generation of DES are coated with polymers with the aim of controlling drug release. The new generation of DES has chosen more complex biocompatible materials (such as PC polymers) and fully biodegradable polymers, such as PLA and PLGA, which can be metabolized to water and carbon dioxide in order to achieve this purpose, thus leaving only a bare metal stent platform locally after complete drug release. Another concept is to avoid the use of polymer coatings. The newly developed intravascular carrier-free drug-eluting stent from LP can avoid both permanent irritation of the vessel wall by non-degradable polymers, which affects endothelialization, and the adverse effects of degradable polymers before degradation and potential side effects during degradation. 2, stent carriers, initially commonly coated drugs are rapamycin (sirolimus), paclitaxel, newly coated drugs are heparin, hirudin and rapamycin analogues: everolimus, tacrolimus, pimecrolimus, etc. There are also Genous endothelial progenitor cell capture stents, γ and β radioactive stents that have been approved by the US FDA, vein-covered stents, metalloproteinase inhibitor-coated stents, vascular endothelial growth factor-coated stents, and 17-β-estradiol-coated stents, among others. In addition, fully biodegradable stents have been developed, which are free of residual stent remnants once completely absorbed, and the local vessels can be repaired.