A write operation method for a phase change memory (PCM) is disclosed. The method includes when a PCM performs a write operation, generating a corresponding voltage pulse signal according to to-be-written data, and applying the voltage pulse signal to a phase change material included in a phase change storage unit corresponding to the to-be-written data and applying the voltage pulse signal to a voltage divider resistor serially connected to the phase change material; comparing voltage values at both ends of a sampling resistor with a threshold voltage to generate an indicator value; determining, according to the indicator value, whether data that is stored in the phase change storage unit and is corresponding to the indicator value is the same as the to-be-written data; and skipping writing if the same; or writing if different, thus reducing the delay time of writing data into the phase change storage unit.