A transmission configuration indication method of a demodulation reference signal, DMRS, port, comprising: configuring, by a network side device, at least two DMRS ports for a terminal according to a required mapping relationship between transmission configuration indication state information, TCI states, and DMRS code division multiplexing, CDM, groups, wherein the at least two DMRS ports belong to different DMRS CDM groups, and the different DMRS CDM groups comprise different quantities of DMRS ports; and sending, by the network side device, downlink control information, DCI, to the terminal, wherein the DCI comprises DMRS port index values, the DMRS port index values are index values pre-defined in a DMRS port allocation table, and the DMRS port index values are used to indicate a set of the at least two DMRS ports configured to the terminal, a number of DMRS CDM groups without data, and a number of front-load DMRS symbols, and are used to indicate the mapping relationship between the TCI states and the DMRS CDM groups; wherein at least one first parameter combination is formed by a DMRS pilot type, a maximum number of front-load DMRS symbols being 1, the number of the DMRS CDM groups without data and a total number of DMRS ports; and for each of the at least one first parameter combination, if a TCI field in the DCI corresponds to at least two TCI states, at least two DMRS port index values corresponding to the first parameter combination correspond to a same mapping relationship between the TCI states and the DMRS CDM groups; and/or at least one second parameter combination is formed by a DMRS pilot type, a maximum number of front-load DMRS symbols being 2, a number of actually used DMRS symbols, the number of the DMRS CDM groups without data and a total number of DMRS ports; and for each of the at least one second parameter combination, if a TCI field in the DCI corresponds to at least two TCI states, at least two DMRS port index values corresponding to the second parameter combination correspond to a same mapping relationship between the TCI states and the DMRS CDM groups. configuring, by a network side device, at least two DMRS ports for a terminal according to a required mapping relationship between transmission configuration indication state information, TCI states, and DMRS code division multiplexing, CDM, groups, wherein the at least two DMRS ports belong to different DMRS CDM groups, and the different DMRS CDM groups comprise different quantities of DMRS ports; and sending, by the network side device, downlink control information, DCI, to the terminal, wherein the DCI comprises DMRS port index values, the DMRS port index values are index values pre-defined in a DMRS port allocation table, and the DMRS port index values are used to indicate a set of the at least two DMRS ports configured to the terminal, a number of DMRS CDM groups without data, and a number of front-load DMRS symbols, and are used to indicate the mapping relationship between the TCI states and the DMRS CDM groups; wherein at least one first parameter combination is formed by a DMRS pilot type, a maximum number of front-load DMRS symbols being 1, the number of the DMRS CDM groups without data and a total number of DMRS ports; and for each of the at least one first parameter combination, if a TCI field in the DCI corresponds to at least two TCI states, at least two DMRS port index values corresponding to the first parameter combination correspond to a same mapping relationship between the TCI states and the DMRS CDM groups; and/or at least one second parameter combination is formed by a DMRS pilot type, a maximum number of front-load DMRS symbols being 2, a number of actually used DMRS symbols, the number of the DMRS CDM groups without data and a total number of DMRS ports; and for each of the at least one second parameter combination, if a TCI field in the DCI corresponds to at least two TCI states, at least two DMRS port index values corresponding to the second parameter combination correspond to a same mapping relationship between the TCI states and the DMRS CDM groups.