A plasma processing method for a plasma processing device is provided. The plasma processing device includes a reaction chamber, multiple Radio Frequency (RF) power supplies with different RF frequency outputs apply RF electric fields to the reaction chamber, the output of at least one pulse RF power supply has multiple output states, and the processing method includes a match frequency obtaining step and a pulse processing step. In the match frequency obtaining step, the output state of the pulse RF power supply is switched to make the reaction chamber have multiple impedances to simulate the impedances in the pulse processing step. The output frequencies of the variable frequency RF power supply are adjusted to match the simulated impedances. The adjusted output frequencies are stored as match frequencies. In the subsequent pulse processing step, the fast switched impedances are instantly matched by the stored match frequencies.