Microwave-promoted Fenton-like reaction, the combination of Fenton-like reagent with microwave, is an efficient method for waste water treatment. In the present paper, the degradation of rhodamine B (a kind of organic dye) using this method was studied. Through numerous experiments, the influences of various parameters including the initial pH value, reaction time, dosage of K2Cr2O7, dosage of H2O2 and microwave were investigated intensively. The characteristic curve of rhodamine B, the concentration-absorbency curve of rhodamine B, the orthogonal optimization tests and comparative tests were given. The mechanism of this reaction was also probed. It is concluded from the experiments that the microwave can accelerate the process of degradation effectively. Under optimal conditions, the overall color removal was more than 99.9% within 9 min. In the study, the method for characterization was entirely UV-Vis spectral analysis.