The invention provides a cross-area access method for an embedded file system, which comprises the following steps that: a, program codes and EFS share a stored critical resource area defined by BANK; and b, the type of an operating instruction is judged, if the operating instruction is a read or write operating instruction, the critical resource area is utilized to perform time-division asynchronous operation on FLASH, and if the operating instruction is a data erasing operating instruction, the data erasing operating instruction is managed in a real-time operation system under the conditionof not influencing normal execution of other application programs. The cross-area access method for the embedded file system introduces a new EFS space allocation mechanism; the time-division asynchronous operation is performed by defining the critical resource protection area and a task machine; the restriction of the BANK boundary of a memory to the division of the EFS space is not required to be considered; the slack space of the memory is fully utilized; and the utilization rate of the FLASH space is improved and the cost is reduced.