An authentication method, wherein the method comprises: sending, by a user equipment, a first request message to a core network element, wherein the first request message is used to request a connectionless transmission service; receiving, by the user equipment, a response message sent by the core network element; determining, by the user equipment, a first authentication result based on the response message; and receiving, by a base station, a first message sent by the user equipment, wherein the first message comprises uplink data, a user equipment identifier, and a first authentication result; sending, by the base station, an authentication request message to a core network element, wherein the authentication request message comprises the user equipment identifier, a group identifier of a group to which the user equipment belongs, or a cell identifier of a cell to which the user equipment belongs; characterized in that the response message sent by the core network element comprises a user equipment identifier allocated by the core network element to the user equipment, or the user equipment identifier and an authentication code allocated by the core network element to the user equipment, wherein the method further comprises: determining, by the core network element, a second authentication result through calculation based on the authentication request message; receiving, by the base station, an authentication response message sent by the core network element, wherein the authentication response message comprises the second authentication result; and comparing, by the base station, the first authentication result and the second authentication result, and sending the uplink data to the core network element if the first authentication result is the same as the second authentication result. sending, by a user equipment, a first request message to a core network element, wherein the first request message is used to request a connectionless transmission service; receiving, by the user equipment, a response message sent by the core network element; determining, by the user equipment, a first authentication result based on the response message; and receiving, by a base station, a first message sent by the user equipment, wherein the first message comprises uplink data, a user equipment identifier, and a first authentication result; sending, by the base station, an authentication request message to a core network element, wherein the authentication request message comprises the user equipment identifier, a group identifier of a group to which the user equipment belongs, or a cell identifier of a cell to which the user equipment belongs; characterized in that the response message sent by the core network element comprises a user equipment identifier allocated by the core network element to the user equipment, or the user equipment identifier and an authentication code allocated by the core network element to the user equipment, wherein the method further comprises: determining, by the core network element, a second authentication result through calculation based on the authentication request message; receiving, by the base station, an authentication response message sent by the core network element, wherein the authentication response message comprises the second authentication result; and comparing, by the base station, the first authentication result and the second authentication result, and sending the uplink data to the core network element if the first authentication result is the same as the second authentication result. determining, by the core network element, a second authentication result through calculation based on the authentication request message; receiving, by the base station, an authentication response message sent by the core network element, wherein the authentication response message comprises the second authentication result; and comparing, by the base station, the first authentication result and the second authentication result, and sending the uplink data to the core network element if the first authentication result is the same as the second authentication result.