The invention relates to a using method of an embedded system with a data splitting and encrypting function. The stored data of the embedded system are effectively separated and stored by splitting and encrypting; the embedded system divides read-in data into body information data and extraction information data on the basis of full-text correlation conversion by taking data blocks as units when writing data to an off-chip nonvolatile memory and respectively writes in different storage media, and file data are safely and effectively separated and stored; the embedded system can read the stored data in the off-chip memory only based on the body information data, the extraction information data correlation and inverse transformation. The using method effectively overcomes various defects in information safety management of existing embedded systems, provides a new, safe and easy method for nonproliferation, anti-theft and anti-crack information safety of the embedded system and resultantly provides an advanced protection function for the embedded system.