The invention relates to the technical field of information security and mobile phone applications, in particular to a recombination method for irrelevant mirror images of a file system. The method includes the mirror image acquisition step, the head mark taking step, the mark confirming step and the group type and head length confirming step. In the mirror image acquisition step, physical mirror images of a mobile terminal are acquired, and physical structures of the physical mirror images are analyzed. In the head marker taking step, front N bytes of each physical block are taken as head marks of the physical block. In the mark confirming step, data of one physical block where the head marks are located are read, whether the physical block is a mapping table or not is judged, if yes, the next step is executed, and if not, the next physical block is skipped, and the head mark taking step is executed again. In the group type and head length confirming step, all mapping information of the heads of one group is traversed, one logical block number is taken out according to the marks, a physical address is calculated according to the formula that the physical address=group physical address offset + group head length + mapping length * marker serial number, the next physical block address is skipped, the head mark taking step is returned, and the process continues to be executed till all the physical block addresses are traversed. Recombination efficiency is high.