A method, an apparatus, and a system for accessing a storage device. The method includes: acquiring, by an I/O adapter, an access request from a virtual machine, where the access request carries virtual address information of a to-be-accessed storage area; generating an access instruction according to the access request, where the access instruction carries the virtual address information and an identifier of a virtual channel of the virtual machine, where the virtual channel corresponds to the virtual machine on a one-to-one basis and is used to connect the corresponding virtual machine to a storage device target, and the storage device target is configured to manage access to the storage device; and sending the access instruction to the storage device target.