The preparation of an AlCl3 catalyst immobilized on gamma-Al2O3 and its regeneration after deactivation have been studied. AlCl3, generated by reacting CCl4 with gamma-Al2O3, was carried by N-2 to a reactor containing the gamma-Al2O3 support. The immobilized AlCl3 catalyst with meso- and macro-pore bimodal structure was shown to be suitable for isobutene oligomerization. The amount of AlCl3 immobilized on the support in terms of AlClx (x = 2.2) was 7.5 wt%. The catalyst exhibited excellent catalytic properties for isobutene polymerization under mild conditions. The average molecular weight of the product was 1000-2500, and its distribution was narrow, around 2.0 in the reaction temperature range 10-40 degreesC. This catalyst showed nearly perfect reactive specificity to isobutene polymerization and remarkable stability. After 2000 h of continuous running, the conversion dropped from 99 to 57%, the selectivity was maintained with little change at about 90%, and the average molecular weight was within the range 1000-1200 under the conditions T = 32 +/- 1 degreesC, LHSV = 2.0 h(-1), and P = 1.0 MPa. Regeneration of the deactivated catalyst was satisfactorily accomplished by treating the used catalyst with a saturated solution of AlCl3 in CCl4 either in situ or ex situ. The activity recovery can be as high as 96%, and the deactivated catalyst can be regenerated repeatedly.