The improvement of storage stability can reduce the segregation degree of modified bitumen to maintain its performance. In order to appraise the stability of the rubber powder modified bitumen and seek the methods for the improvement of its stability, tests were done to analyze the effect of microwave radiation and stabilizer on the stability of the rubber powder modified bitumen. The tests indicate that microwave radiation can improve the stability of the rubber powder modified bitumen, and when the dosage of the stabilizer is 5% of the rubber powder's quantity, the improvement on the stability is best. This paper can provide reference and guidance for the engineering application of rubber powder modified bitumen.