Abstract: The inventions disclosed herein provide a crash-proof cache data protection method and system. The cache data backup steps include: when power interruption unexpectedly occur, a preselected central processing unit receiving an interrupt request signal; querying to obtain index nodes of block devices corresponding to logical volume management volumes; according to the index nodes, acquiring a page needing to be stored in a flash memory; acquiring a buffer head in the page, and storing information of the buffer head and buffer data corresponding to the buffer head into the flash memory, and generating backup data.