The invention discloses a data storage method based on NandFlash. The NandFlash is partitioned into two data storage areas in the same size, a bad block area and a backup data area, a corresponding mapping table is established, and available blocks in the backup data area can replace bad blocks once bad blocks exist in the data storage areas. By defining a data structure as 4-byte index, 2-byte flag bit, user data and 2-byte CRC16, the next data record can be quickly positioned, the data storage reliability is guaranteed, and data deletion operation can be performed by rewriting flag bits. The data storage method can be widely applied to occasions where data storage and data retrieval in small and medium-sized embedded systems are required, and has the characteristics of high access speed, high storage efficiency and good reliability.