Safety protection method for flash program of single-chip computer and protection device and single-chip computer

The invention discloses a safety protection method for a flash program of a single-chip computer. The method comprises following steps: S11, obtaining an input password; S12, determining whether the input password is equal to a password value of a password information area of the single-chip computer and entering the step S13 if is and entering the step 14 if not; S13, removing the restriction of an access restriction door of the single-chip computer and resetting the number of changes of data in the password region of the single-chip computer; S14, maintaining the restriction of the access restriction door and increasing number of changes in data of the password region by one; S15, eliminating all data information saved by a flash of the single-chip computer when the number of changes of data in the password region reaches the set value. The protection method utilizes the programming characteristics of flash to achieve safety protection of the program and is simple in design. When the number of changes of da