File operation method and device

The invention discloses a file operation method and device. The method comprises the steps that file information sent by a client side is received, wherein the file information is the file information of an unknown file which is requested to be opened by the client side, and the file information comprises at least one of file header information and filename suffix information; a file format of the unknown file is identified according to the file information, and application information used for opening application of the unknown file is obtained according to the file format; corresponding file operation steps are determined according to whether the application information is matched with preset information or not; treatment is conducted on the unknown file to present the file content of the unknown file according to the file operation steps. According to the file operation method and device, the flexibility of treatment of the unknown file is improved.