A flash device access method, apparatus, and system, where a flash device includes a controller and a storage array. The method includes dividing the storage array into a specific storage unit and a user storage unit, such that a storage feature of the specific storage unit is the same as that of the user storage unit, writing, by the controller, specific data into the specific storage unit, reading, by the controller, the specific data stored in the specific storage unit, determining, by the controller, a decision voltage (Vread) based on the read specific data, and reading, by the controller using the determined Vread, the user data stored in the user storage unit. Hence, incorrect determining of the data stored in the flash device may be reduced using the access method, apparatus, and system.