A data synchronization method for a multi-level associative storage architecture includes: receiving, by a master module, a request of an external write operation, writing data into a write buffer of the master module, and recording a digit sequence according to the write operation on the write buffer of the master module; flushing data from the write buffer to solid-state disk (SSD) files when a data amount in the write buffer of the master module reaches a threshold; recording, by the master module, a digit sequence for a flush operation; separately synchronizing, by the master module, the write operation and the flush operation to a slave module according to orders of digits in different digit sequences; and receiving, by the slave module, the synchronous write operation and synchronous flush operation, and separately synchronizing the data of the master module to corresponding locations of a local write buffer and local SSD files.