A PCIe-based data transmission method and an apparatus are provided. The method includes the following: A first node obtains and sends a first TLP; and a switch receives the first TLP, and sends a second TLP to a second node. The first TLP includes a first TLP header and a first data payload, the second TLP includes a second TLP header and the first data payload, the first TLP header and the second TLP header are used to indicate a data type of the first data payload, and the data type of the first data payload includes at least one of audio, an image, control, data stream write, or security. The second node obtains the first data payload based on the data type of the first data payload. This helps reduce communication complexity in a high-speed communication scenario.