File safe distribution method based on universal series bus (USB) flash disk

The invention relates to a file safe distribution method based on a universal series bus (USB) flash disk. Validity of a user identity is confirmed based on identity authentication based on a USB flash disk chip serial number, and the safe distribution and safe use of an Excel file is ensured by using methods of a custom specific code, message digest (MD) 5 validation, secondary encryption and the like. In the process of distribution and use of the Excel file, the file safe distribution method based on the USB flash disk enhances the protection to file contents and the authentication of the user identity, and enables the Excel file to be distributed and used safely and reliably. The USB flash disk chip serial number instead of a computer hard disk serial number is bound, and convenience is achieved as the USB flash disk is easy to carry and can be used in different computers by a user.