An authentication method and a method for transmitting authentication information, and the method for transmitting authentication information includes: an MS and a network agree in advance one or more agreed operations to be performed when the network determines that the SQNMS is an agreed value; the MS generating an authentication resynchronization token (AUTS) by using the agreed value, sending a resynchronization request containing the AUTS to the network; upon receiving the resynchronization request and determining that the SQNMS of the AUTS is the agreed value, the network performing the one or more agreed operations. The method of transmitting authentication information from the MS to the network conveniently implement the information transmitting between the MS and the network and guarantee the network security without increasing and changing the existing signaling resources and authentication parameters.