In this work, we prepared different initiator solutions containing ether and AlCl3 by changing the addition sequence of ingredients, studied the interactions between ether and AlCl3 from the evolution of the Fourier transform infrared (FTIR) spectra by comparison, and investigated the catalytic performances of AlCl3 affected by ether for isobutylene polymerization. We observed that different preparation methods of initiator solutions could lead to two kinds of interactions between ether and H2O/AlCl3 in hexane. The strong interaction could stabilize carbenium ions and seriously decrease the catalytic performance, whereas the weak interaction could promote isomerization and proton elimination. Moreover, we found that the preparation method of initiator solutions was not a critical factor in CH2Cl2. Finally, a universal mechanism based on the AlCl3-involved interactions in different solvents was proposed to understand the effects of ether on the cationic polymerization catalyzed by AlCl3 thoroughly.