An information protection method and device based on a plurality of sub-areas for an MCU chip, the MCU chip comprises an instruction bus, a data bus, a flash controller and a user area of a flash memory, the method comprises: determining a preceding sub-area when the instruction bus accesses the user area; entering corresponding preceding sub-area working state; determining the current sub-area when the instruction bus accesses the user area; when the preceding sub-area is inconsistent with the current sub-area, entering the transition state; determining whether the duration of the transition state reaches the preset waiting time; if yes, entering the corresponding current sub-area working state. The information protection method and device prevent the cooperative companies which develop the program together from stealing program from each other.