Ultrasonic emulsion polymerization, which allows low surfactant concentration and absence of any chemical initiator, is advantageous from the viewpoint of green Sustainable chemistry. In this Study, polymerization of styrene under unsteady indirect ultrasonic irradiation was investigated. The position of the reactor was changed in two steps depending on the progress of the polymerization. In the first step, the reactor was set at the position where the induction period was short. On the other hand, in the second step, the reactor was set at the position where the effect of degradation of the polymer was small. The effects of the irradiation time in the first step and position of the reactor in the second step on the molecular Weight distribution were Studied. The proposed dynamic process operational method by changing irradiation conditions with the progress of the polymerization is efficient for intensification of emulsion polymerization process.