An image filing method including following steps is provided. At least one sheet is searched form from a plurality of scan image data by an office machine or a computer connected to the scanner. the plurality of scan image data is divided into M groups, and the at least one sheet form is set up in a first image data of each of M groups when there are M sheet forms searched from the plurality of scan image data, wherein M is an integral larger than 1. A keyword string is searched in each of the M sheet forms and an encoded string arranged after the keyword string is identified. M files corresponding to the M groups are created and named according to the encoded strings in each of the M sheet forms.