An uplink data transmission method, wherein the method is performed by a terminal device, and the method comprises: receiving a message comprising indication information, wherein the indication information is used to enable the terminal device to determine, according to the indication information, at least two contention transmission units, CTUs, in a same transmission time interval, TTI, for uplink data transmission, the CTU refers to a transmission resource combining a time, a frequency, and a code domain, or a transmission resource combining a time, a frequency, and a pilot, or a transmission resource combining a time, a frequency, a code domain, and a pilot; transmitting uplink data by using the at least two CTUs, wherein the uplink data transmitted by using the at least two CTUs is partially same or totally same; wherein the indication information comprises at least one type of the following information: information about a dedicated connection signature, DCS, of the terminal device; information about a quantity of CTUs that can be used for the terminal device to transmit the uplink data; information about a CTU access region; information about a quantity of CTUs in a CTU access region; information about a starting CTU in a CTU access region; or information about a CTU-sequence-number mapping rule; wherein the CTU access region comprises multiple CTU access regions, wherein the multiple CTU access regions are CTU access regions belonging to a same TTI. receiving a message comprising indication information, wherein the indication information is used to enable the terminal device to determine, according to the indication information, at least two contention transmission units, CTUs, in a same transmission time interval, TTI, for uplink data transmission, the CTU refers to a transmission resource combining a time, a frequency, and a code domain, or a transmission resource combining a time, a frequency, and a pilot, or a transmission resource combining a time, a frequency, a code domain, and a pilot; transmitting uplink data by using the at least two CTUs, wherein the uplink data transmitted by using the at least two CTUs is partially same or totally same; wherein the indication information comprises at least one type of the following information: information about a dedicated connection signature, DCS, of the terminal device; information about a quantity of CTUs that can be used for the terminal device to transmit the uplink data; information about a CTU access region; information about a quantity of CTUs in a CTU access region; information about a starting CTU in a CTU access region; or information about a CTU-sequence-number mapping rule; wherein the CTU access region comprises multiple CTU access regions, wherein the multiple CTU access regions are CTU access regions belonging to a same TTI. information about a dedicated connection signature, DCS, of the terminal device; information about a quantity of CTUs that can be used for the terminal device to transmit the uplink data; information about a CTU access region; information about a quantity of CTUs in a CTU access region; information about a starting CTU in a CTU access region; or information about a CTU-sequence-number mapping rule; wherein the CTU access region comprises multiple CTU access regions, wherein the multiple CTU access regions are CTU access regions belonging to a same TTI.