Disclosed in the present application are a data transmission method, a terminal device, and a network device. The method comprises: a terminal device receives first indication information, the first indication information comprising information about multiple time-domain resources, and frequency channel numbers located on different time-domain resources among the multiple time-domain resources and used for data transmission being different; and the terminal device transmits data on the multiple time-domain resources according to the frequency channel numbers corresponding to the multiple time-domain resources. Accordingly, the terminal device can transmit data according to different frequency channel numbers, without increasing hardware costs and power consumption of the terminal device.