Abstract: The two-dimensional multi-bits alarm method (TDMBAM) is proposed to reduce the damage of system security caused by RAM faults. The proposed method is based on two-dimensional error correction code. TDMBAM is able to correct multiple bit faults of RAM with any possible width and evaluate the error correcting capacity of two-dimensional code and RAM faults type. TDMBAM is designed to have partitioned protection for RAM with program memory block and data memory block, and has two different error correcting alarm circuits according to the respective characteristics of two memory blocks. TDMBAM is simulated and the results show that it is able to correct all continuous and discontinuous faults within the given width, and able to alarm faults beyond identification. Up to 99.147 7% alarmed systems are able to work in schedule without system faults.