A data transmission method, comprising: receiving, by a terminal device, first control information sent by a network device, wherein the first control information is used to instruct the terminal device to receive, on a first time-frequency resource, a first transport block sent by the network device at an n th time; receiving, by the terminal device, the first transport block on the first time-frequency resource; and receiving, by the terminal device, first indication information sent by the network device, wherein the first indication information is used to indicate a first code block group CBG in the first transport block, and the first CBG corresponds to a second time-frequency resource during the n th time transmission of the first transport block, wherein n is an integer greater than or equal to 0; wherein the method further comprises: receiving, by the terminal device, second indication information sent by the network device, wherein the second indication information is used to indicate a third time-frequency resource, and an intersection set between the third time-frequency resource and the first time-frequency resource is a fourth time-frequency resource; and determining, by the terminal device, a fifth time-frequency resource, wherein the fifth time-frequency resource comprises at least one resource element RE, the at least one RE is comprised in the first time-frequency resource, and received signals on the fifth time-frequency resource comprise a signal that is not used for the terminal device to decode the first transport block; characterized in that if there is no intersection set between the second time-frequency resource and the fourth time-frequency resource, the fifth time-frequency resource is the first time-frequency resource. receiving, by a terminal device, first control information sent by a network device, wherein the first control information is used to instruct the terminal device to receive, on a first time-frequency resource, a first transport block sent by the network device at an n th time; receiving, by the terminal device, the first transport block on the first time-frequency resource; and receiving, by the terminal device, first indication information sent by the network device, wherein the first indication information is used to indicate a first code block group CBG in the first transport block, and the first CBG corresponds to a second time-frequency resource during the n th time transmission of the first transport block, wherein n is an integer greater than or equal to 0; wherein the method further comprises: receiving, by the terminal device, second indication information sent by the network device, wherein the second indication information is used to indicate a third time-frequency resource, and an intersection set between the third time-frequency resource and the first time-frequency resource is a fourth time-frequency resource; and determining, by the terminal device, a fifth time-frequency resource, wherein the fifth time-frequency resource comprises at least one resource element RE, the at least one RE is comprised in the first time-frequency resource, and received signals on the fifth time-frequency resource comprise a signal that is not used for the terminal device to decode the first transport block; characterized in that if there is no intersection set between the second time-frequency resource and the fourth time-frequency resource, the fifth time-frequency resource is the first time-frequency resource. receiving, by the terminal device, second indication information sent by the network device, wherein the second indication information is used to indicate a third time-frequency resource, and an intersection set between the third time-frequency resource and the first time-frequency resource is a fourth time-frequency resource; and determining, by the terminal device, a fifth time-frequency resource, wherein the fifth time-frequency resource comprises at least one resource element RE, the at least one RE is comprised in the first time-frequency resource, and received signals on the fifth time-frequency resource comprise a signal that is not used for the terminal device to decode the first transport block; characterized in that if there is no intersection set between the second time-frequency resource and the fourth time-frequency resource, the fifth time-frequency resource is the first time-frequency resource.