A method for transmitting data in the Internet of Vehicles, and a terminal device are provided. Resources used for repeated sidelink transmission may be determined, which is beneficial in improving the reliability of data transmission. The method includes that a terminal device receiving first control information sent by a network device. The first control information is used to determine resource information used for repeated sidelink transmission. The method also includes that according to the first control information, the terminal device determining resources used for repeated sidelink transmission.