Embodiments of the present invention provide a data transmission method, apparatus, and system. The method is applied to a data transmission system. The data transmission system includes a system platform and a terminal device. A method performed by the system platform includes: determining, based on a type of the terminal device and a type of data generated by the terminal device, a data transmission rule of the data generated by the terminal device; and sending a data transmission message to the terminal device, where the data transmission message carries the data transmission rule, so that the terminal device sends, to the system platform based on the data transmission rule, the data corresponding to the data transmission rule. Massive data can be effectively prevented from being transmitted to the system platform by configuring the data transmission rule, and data with a high priority can be preferentially processed, to improve system performance.