Abstract: The effect of capping agent, 1,1-diphenylethene(DPE), on the aggregating state of n-butyllithium(n-BuLi) was studied using 7Li-NMR. Results showed that DPE would dissociate the big aggregators to hexamers in n BuLi, while it could not further affect the hexamers. There was a change point in the conversion time relationship of the bulk polymerization of styrene initiated by DPHLi, where existed supramolecules before the change point. The supramolecules were dissociated during the polymerization. After the change point, the supramolecules were dissociated completely, and the polymerization was proceeding faster.