The invention relates to a coding method for prolonging NAND Flash data reliable storage time, and aims to solve the problems in the prior art that the NAND Flash data reliable storage time is short, the computing cost of the LDPC algorithm is high, the computing capability requirements of a hardware are high, and data backup needs to be rewritten. The coding method is realized through the following steps: 1, obtaining corresponding continuous reliable storage time length; 2, iteratively executing the step 1 after the data is read each time; 3, after the step 2 is executed, comparing T and T, and if reaching the T, executing the step 4, otherwise, executing the step 5; 4, starting up an out-of-place updating mechanism of the data; 5, reading the data; 6, executing ECC error correction; 7, judging whether the storage time length of the data reaches T, and if yes, executing the step 8, and if no, executing the step 9; 8, when T reaches the T, executing the step 2 and the step 9; 9, obtaining the correct data; 10, ending. The coding method is applied to the field of data storage.