PCM (pulse code modulation) write operation method

The invention discloses a phase change memory write operation method. The method comprises the following steps: S1, preprocessing a data block to be written back to a PCM storage unit to acquire a preprocessed data block; S2, reading an initial data block corresponding to the data block to be written from the PCM storage unit; and S3, calculating a Hamming distance between the data block to be written or the preprocessed data block and the initial data block, selecting the data block corresponding to the minimum value of the Hamming distance to the initial data block, and writing the data block back to the initial data block, and writing a preprocessing mark back to the storage unit. The method reduces the times of write operation on the PCM storage unit, so the service life of the PCM is prolonged.