A data protection method, a memory storage device and a memory control circuit unit are provided. The method includes: setting a plurality of disk array tags corresponding to a plurality of word lines and a plurality of memory planes, and the plurality of disk array tags corresponding to one of the word lines connected to one of the memory planes are at least partially identical to the plurality of disk array tags corresponding to another one of the word lines connected to another one of the memory planes; receiving a write command and data corresponding to the write command from a host system; and sequentially writing the data into the plurality of word lines and the plurality of memory planes corresponding to the plurality of disk array tags.