Embodiments of this application provide a data transmission method and a communication apparatus. The method includes: A network device sends indication information to a terminal device, where the indication information is used to indicate a first transmission mode, and the first transmission mode includes: enabling a hybrid automatic repeat request function, disabling the hybrid automatic repeat request function, or at least one hybrid automatic repeat request mode. Therefore, after receiving the indication information sent by the network device, the terminal device determines the first transmission mode based on the indication information, and performs data transmission in the first transmission mode, to perform data transmission based on requirements of different services. In this way, flexibility of the data transmission is improved.