A method for automatically identifying a release of a Microsoft Windows Operating System, OS, of a host by a Universal Serial Bus, USB, device, comprising: after a USB device is plugged into the host and the host issues a USB request to acquire a device descriptor, a configuration descriptor, and an interface descriptor, reporting, by the USB device to the host, a number of M configurations (11, 201), M being an integer greater than 1, wherein the USB device comprises configuration descriptors corresponding respectively to the M configurations; during a process of enumerating the USB device as a Trans-Flash, TF, card device, reporting, by the USB device, to the host, a Microsoft OS Descriptor, MOSD, supporting configuration designation designating a configuration value as the Nth configuration (12, 202), N being an integer greater than 1 and no greater than M, such that the host issues a request to acquire any specifics of a configuration according to the USB-reported number of configurations; detecting, by the USB device, whether the host has acquired a configuration descriptor corresponding to the Nth configuration; when detecting that the host has acquired a configuration descriptor corresponding to the Nth configuration, determining, by the USB device, that a release of a present Microsoft Windows OS is Win8 (13, 204); when detecting that the host has acquired a configuration descriptor not corresponding to the Nth configuration, determining, by the USB device, whether the USB device has received only one INQUIRY instruction issued by the host, wherein the INQUIRY instruction is an SCSI instruction for returning information on a present Logic Unit, LUN; when having determined that the USB device has received only one INQUIRY instruction issued by the host, determining, by the USB device, that a release of a present Microsoft Windows OS is XP; when having determined that the USB device has received at least two INQUIRY instructions issued by the host, determining, by the USB device, that a release of a present Microsoft Windows OS is Vista or Win7 (14, 207). after a USB device is plugged into the host and the host issues a USB request to acquire a device descriptor, a configuration descriptor, and an interface descriptor, reporting, by the USB device to the host, a number of M configurations (11, 201), M being an integer greater than 1, wherein the USB device comprises configuration descriptors corresponding respectively to the M configurations; during a process of enumerating the USB device as a Trans-Flash, TF, card device, reporting, by the USB device, to the host, a Microsoft OS Descriptor, MOSD, supporting configuration designation designating a configuration value as the Nth configuration (12, 202), N being an integer greater than 1 and no greater than M, such that the host issues a request to acquire any specifics of a configuration according to the USB-reported number of configurations; detecting, by the USB device, whether the host has acquired a configuration descriptor corresponding to the Nth configuration; when detecting that the host has acquired a configuration descriptor corresponding to the Nth configuration, determining, by the USB device, that a release of a present Microsoft Windows OS is Win8 (13, 204); when detecting that the host has acquired a configuration descriptor not corresponding to the Nth configuration, determining, by the USB device, whether the USB device has received only one INQUIRY instruction issued by the host, wherein the INQUIRY instruction is an SCSI instruction for returning information on a present Logic Unit, LUN; when having determined that the USB device has received only one INQUIRY instruction issued by the host, determining, by the USB device, that a release of a present Microsoft Windows OS is XP; when having determined that the USB device has received at least two INQUIRY instructions issued by the host, determining, by the USB device, that a release of a present Microsoft Windows OS is Vista or Win7 (14, 207).