A method of file system prefetching is provided. The method is applicable to an electronic device including a volatile storage, a non-volatile storage, and multiple processors with multiple operating systems. The method includes the following steps. When a first static backup table in the non-volatile storage is not empty, copy all data in the first static backup table to a second static backup table in the volatile storage. Check whether the first static backup table includes all required data for booting one of the operating systems in a static partition of the non-volatile storage. When the first static backup table does not include all of the required data, copy a part of the remaining required data in the static partition to the first and the second static backup tables. Return to the checking step when a booting state synchronization of the operating systems is not completed yet.