On the basis of in-depth understanding the Flash chips,this paper designs a new program which using the SCM to detect the invalid block.Mainly through reading the data of the first and second page to detect the invalid block.Specific implementation procedure was given,and the key circuit schematic diagram and C language program code was introduced.This design achieved the function of using the MCU checks the invalid block finally,and increased the function by reading the ID number of Flash to get the performance of the memory.And the design also can write and read1GB data