The functional requirements should be determined according to the application, because different use environments have different functional priorities. As an electronic door lock for offices of financial institutions, it must have the following functions: time limit function for all key cards, door opening record function for locks, and hierarchical management function. On the basis of basic functions, in order to adapt to the future development, we can consider the expansion of the lock system (the system can manage staff offices, public channels, private channels, etc.), the technical interface of the card system and other issues, so that we can monitor the status of the room door in real time, and control the opening of the door under extraordinary circumstances. The best solution is to connect the door locks online and consider the interfaces of other IC card systems together to achieve all-in-one card.