The invention discloses a one-key login method. The method comprises the following steps: if a one-key login operation is detected, calling, by a client, an SDK interface to send first verification information to a gateway server in the form of a short message; calling the SDK interface to send a login request message to an SDK server, wherein the login request message carries second verificationinformation; obtaining, by the gateway server, the identifier of the user who sends the short message, and sending the first verification information and the user identifier to the SDK server; comparing, by the SDK server, the first verification information and the second verification information; if the comparison is successful, sending a generated authentication success message to the client, wherein the authentication success message comprises the user identifier, and the authentication success message is used for characterizing that the client can use the user identifier as a login account; and performing, by the client, user login according to the authentication success message. The invention further discloses a one-key login system, a client, a gateway server and a computer readablestorage medium.