This application discloses an authentication method for accessing a network, an authentication device, and a user device. The method includes: an authentication device receives an authentication response message sent by user device, where the authentication response message includes first data, and the first data is data obtained by the user device based on biometric feature data of a target user. The authentication device obtains second data from a server, where the second data is data obtained by the server based on biometric feature data of a user, and generates indication information when the first data is the same as the second data, where the indication information is used to indicate that the user device is authenticated. The authentication device sends the indication information to the user device.