欧盟划分医疗器械产品风险登记的原则是从医疗器械之设计及制造对人体可能带来的危险程度来进行考量的。目前医疗器械的大类分为医疗器械一、二、三类产品，但由于二类产品又分出了不同的子类，因此实际上可将医疗器械分为以下4类:

①Class I 低风险 (Low risk) ，其中 Is、Im、Ir类：灭菌器械（s）、带测量功能器械（m）、重复使用外科器械（r）

②Class IIa 低到中风险 (Low to medium risk) ，包括普通非植入器械和普通植入器械。

③Class IIb 中风险 (Medium risk) ，包括技术成熟的植入器械和技术不成熟的植入器械、植入器械、MDR附录VIII第12条规定的器械。

④Class III 高风险 (High risk) ，包括特殊非植入器械和特殊植入器械、MDR附录VIII第21条规定的器械。

The EU's principle of classifying medical device product risk registration is to consider the possible risks to human body caused by the design and manufacture of medical devices. At present, the major categories of medical devices are divided into Class I, II and III products. However, since Class II products are divided into different subcategories, medical devices can actually be divided into the following four categories:

① Class I Low risk, including Is, Im, Ir: sterilized instruments (s), instruments with measuring function (m), and reusable surgical instruments (r)

② Class IIa is low to medium risk, including ordinary non implant devices and ordinary implant devices.

③ Medium risk in Class IIb includes implant devices with mature technology and implant devices with immature technology, implant devices, and devices specified in Article 12 of MDR Appendix VIII.

④ Class III high risk, including special non implant devices and special implant devices, and devices specified in Article 21 of MDR Appendix VIII.