An uplink data transmission method and device are provided. The method includes: receiving, by a network device, a control symbol sent by a terminal device by using a control time-frequency resource, wherein the control symbol carries control information, wherein the control information indicates a data encoding scheme at the terminal device, wherein the control time-frequency resource belongs to a transmission resource that includes a data time-frequency resource, and wherein the control time-frequency resource and the data time-frequency resource are different; demodulating and decoding, at the network device, the control symbol to obtain the control information; and decoding, at the network device and according to the control information, a data symbol to obtain uplink data, wherein the data symbol is received from the terminal device by way of the data time-frequency resource.