The present invention provides a fingerprint authentication method, a connection device, and a terminal device. The method comprises: receiving authentication request information sent by a terminal device; acquiring partial encrypted fingerprint data from a storage partition according to the authentication request information; decrypting all the acquired partial encrypted fingerprint data, and processing all the partial decrypted fingerprint data to obtain original fingerprint data; and sending the original fingerprint data to the terminal device. According to the present invention, fingerprint data of valid users is split and encrypted in advance, and then encrypted partial fingerprint data is separately stored in each storage partition of a connection device. In the present invention, the fingerprint data of the valid users is not stored in a terminal device. Therefore, even if the terminal device is lost, illegal users cannot acquire the fingerprint data of the valid users by attacking the system core of the terminal device, thereby ensuring security of the terminal device.