The embodiments of the invention provide a password updating method, user equipment (UE), a user position server and a domain router. The password updating method comprises the following steps: receiving first secret key negotiation parameters sent by an SLS, wherein the first secret key negotiation parameters are generated by the SLS according to a secret key of the SLS by use of a secret key exchange algorithm; according to a secret key of UE, generating second secret key negotiation parameters by use of the secret key exchange algorithm; according to the second secret key negotiation parameters and an original password, obtaining protection identifications of the second secret key negotiation parameters; according to the first secret key negotiation parameters, the secret key of the UE and a destination password, obtaining a protection identification of the destination password; and sending the protection identifications of the second secret key negotiation parameters and the protection identification of the destination password to the SLS, wherein the protection identifications of the second secret key negotiation parameters are used for enabling the SLS to obtain the destination password according to the original password, the second secret key negotiation parameters, the secret key of the SLS and the protection identification of the destination password. According to the embodiments of the invention, the password updating security can be improved.