The invention discloses a dynamic authentication method between a reader and a tag card and an implementation device thereof for solving the technical problem that the traditional authentication method must depend on real-time online reliable and safe connection with a backstage database, and cannot authenticate the tag card with the reader autonomously at a high degree. In the method, only a legal reader can acquire corresponding tag authentication information from an authentication database to authenticate or update the state of the corresponding tag; only a legal tag can be processed by the legal reader; a dynamic updating mechanism is applied to the tag identification (ID) in the authenticating process to ensure the forward security, and the reader stores the tag card information by adopting a Hash table, thereby improving the authentication speed; and data synchronization is realized skillfully in an attribute value mode; and the use of random numbers ensures that different data packets can be used in each authentication, so that the position information of the tag is effectively concealed and high security characteristic is provided.