In a data access method, a processor of a host converts a first descriptor recognized by a virtual machine interface card of the virtual machine into a second descriptor recognized by a physical interface card of the host. The first descriptor includes a virtual machine physical memory address and a data length of accessible data. The physical interface card of the host obtains, based on the second descriptor, a physical address that is in a memory and to which the virtual machine physical memory address is mapped, and accesses the accessible data according to the physical address in the memory.