A first node obtains a corresponding physical address based on a first virtual address in a first request. The first request may be sent by an application in the first node, and is used to request to read data of a second node or request to write data to the second node. Then, the first node sends a second request corresponding to the first request to the second node based on a first mapping relationship. Because the bus address indicates a virtual address corresponding to an instance of the second node, when the virtual address may be accessed by the first node based on the first request, the virtual address may be accessed by the second node, or may be accessed by another node based on a request, to implement address sharing in data access.