An identity authentication method, comprising: detecting, by a first device, that a biological limb of a human body is in contact with the first device and establishing, by the first device, an intra-body communication connection with a second device via the biological limb, the second device being a device implanted in the human body receiving, by the first device, data to be authenticated transmitted by the second device via the intra-body communication connection, the data to be authenticated comprising digital authentication information and an identity identifier associated with the second device; collecting, by the first device, biological characteristic information of part of the biological limb touching the first device when the biological limb touches the first device during a time period in which the intra-body communication connection is established with the second device; sending, by the first device, the data to be authenticated and the biological characteristic information to a background server; receiving, by the background server, the data to be authenticated and the biological characteristic information; obtaining (S 112), by the background server, a pre-stored authentication factor and biological characteristic verification information corresponding to the identity identifier; performing (S 114), by the background server, an authentication on the digital authentication information according to the authentication factor, and determining whether a matching rate between the biological characteristic information and the biological characteristic verification information is greater than a first preset value, the first preset value being smaller than a second preset value, the second preset value referring to a matching rate indicating that two pieces of biological characteristic information are identical; and when the authentication performed on the digital authentication information is passed and the matching rate between the biological characteristic information and the biological characteristic verification information is greater than the first preset value, determining that an identity authentication for the second device is passed. detecting, by a first device, that a biological limb of a human body is in contact with the first device and establishing, by the first device, an intra-body communication connection with a second device via the biological limb, the second device being a device implanted in the human body receiving, by the first device, data to be authenticated transmitted by the second device via the intra-body communication connection, the data to be authenticated comprising digital authentication information and an identity identifier associated with the second device; collecting, by the first device, biological characteristic information of part of the biological limb touching the first device when the biological limb touches the first device during a time period in which the intra-body communication connection is established with the second device; sending, by the first device, the data to be authenticated and the biological characteristic information to a background server; receiving, by the background server, the data to be authenticated and the biological characteristic information; obtaining (S 112), by the background server, a pre-stored authentication factor and biological characteristic verification information corresponding to the identity identifier; performing (S 114), by the background server, an authentication on the digital authentication information according to the authentication factor, and determining whether a matching rate between the biological characteristic information and the biological characteristic verification information is greater than a first preset value, the first preset value being smaller than a second preset value, the second preset value referring to a matching rate indicating that two pieces of biological characteristic information are identical; and when the authentication performed on the digital authentication information is passed and the matching rate between the biological characteristic information and the biological characteristic verification information is greater than the first preset value, determining that an identity authentication for the second device is passed.