A duplication transmission method (200, 600), comprising: receiving (201, 601), by a terminal device (110, 900, 1000), duplication transmission configuration information sent by a radio access network, RAN, device, through media access control, MAC, configuration signaling, wherein the duplication transmission configuration information comprises configurations of a duplication transmission mode and duplication transmission content of the terminal device (110, 900, 1000); and performing (202, 602), by the terminal device (110, 900, 1000), duplication transmission based on the duplication transmission configuration information, wherein the duplication transmission configuration information is used to instruct the terminal device (110, 900, 1000) to activate or de-activate the duplication transmission, wherein the duplication transmission mode is used to instruct the terminal device (110, 900, 1000) whether to perform the duplication transmission, and the duplication transmission content is used to indicate a data radio bearer, DRB, on which the terminal device performs the duplication transmission, wherein the MAC configuration signaling includes: an identity of a logical channel, LC, LogicalChannelIdentity, corresponding to the DRB and duplication transmission indication of the LC; or an identity of a logical channel group, LCG, corresponding to the DRB and duplication transmission indication of the LCG, and wherein performing by the terminal device, duplication transmission based on the duplication transmission configuration information further includes: when a quantity of retransmission times of an Automatic Repeat Request, ARQ, of the LC whose identity is LogicalChannelIdentity in the DRB whose identity is DRB-Identity is higher than an ARQ-threshold, duplication transmission of the data of the LC is triggered. receiving (201, 601), by a terminal device (110, 900, 1000), duplication transmission configuration information sent by a radio access network, RAN, device, through media access control, MAC, configuration signaling, wherein the duplication transmission configuration information comprises configurations of a duplication transmission mode and duplication transmission content of the terminal device (110, 900, 1000); and performing (202, 602), by the terminal device (110, 900, 1000), duplication transmission based on the duplication transmission configuration information, wherein the duplication transmission configuration information is used to instruct the terminal device (110, 900, 1000) to activate or de-activate the duplication transmission, wherein the duplication transmission mode is used to instruct the terminal device (110, 900, 1000) whether to perform the duplication transmission, and the duplication transmission content is used to indicate a data radio bearer, DRB, on which the terminal device performs the duplication transmission, wherein the MAC configuration signaling includes: an identity of a logical channel, LC, LogicalChannelIdentity, corresponding to the DRB and duplication transmission indication of the LC; or an identity of a logical channel group, LCG, corresponding to the DRB and duplication transmission indication of the LCG, and wherein performing by the terminal device, duplication transmission based on the duplication transmission configuration information further includes: when a quantity of retransmission times of an Automatic Repeat Request, ARQ, of the LC whose identity is LogicalChannelIdentity in the DRB whose identity is DRB-Identity is higher than an ARQ-threshold, duplication transmission of the data of the LC is triggered.