The invention provides a stability maintenance device for modified asphalt, and belongs to the technical field of road surface construction equipment. The stability maintenance device for modified asphalt comprises a stability maintenance tank, a firs temperature regulating and controlling device, a second temperature regulating and controlling device, a first stirring device, a second stirring device and a computer control system. According to the stability maintenance device provided by the invention, the stirring device and the temperature regulating and controlling devices arranged on top of the tank body and the bottom of the tank body are separately controlled by the computer control system, so that modified asphalt is stirred at a high speed at a proper temperature in the storage tank, occurrence of a modified asphalt segregation phenomenon is avoided, and stability of modified asphalt is sufficiently maintained.