The dye waste solution is a big pollution issue of textile industry due to its toxic substance and color. Advanced oxidation processes (AOPs) produce reactive radicals such as OH, H and O radicals to oxidize the organic dye solution then remove its color. The pulsed discharge is one way to produce these radicals. However, the pulse voltage used is about tenths of kilovolts. In this study, the RF pen-like plasma was used to decolorize the dye solution, with the hope to replace the pulsed discharge system. The results show that the color of the dye waste water was successfully removed by the atmosphere RF pen-like plasma system. The key parameters to affect decoloration are power, the volume of waste water and the processing time. If one integrates the power, processing time and the volume as consumed energy per unit volume, one will find a trackable correlation between decoloration and the consumed energy per unit volume. The relationship between decoloration and consumed energy per unit volume is D=35.29 *ln(E)−142.38, using the atmosphere RF pen-like plasma system; D=decoloration (%), E=consumed energy per unit volume (J/ml).