Self-check system and method thereof

A self-check system and a method thereof are disclosed. In the self-check system, a memory stores a safety check program, a main application program and a predetermined checksum data. The safety check program include a circuit check program, a watchdog circuit reset program and a checksum check program. When a chip system is powered on, a processing unit executes the main application program, and then executes an interrupt call to generate an interrupt, so as to execute the safety check program and the circuit check program to check a to-be-checked circuit. The processing unit also executes the watchdog circuit reset program to reset a counting value of a watchdog circuit. The processing unit also executes the checksum check program to calculate a checksum data of the first safety check program, and reset the chip system when the calculated checksum data is not equal to the predetermined checksum data.