A roll caster, which could cast the three layers of clad strip directly from the molten metal, was designed, assembled and tested. The base strip was AA3003 aluminum alloy and overlay strips were AA4045 aluminum alloy. An unequal diameter twin roll caster was modified to cast clad strip. Two small rolls were amounted on a large roll. A scraper plate was used to prevent the mixture of the different kinds of melts. The casting of three strips and the connecting of strips could be operated by one roll caster. The interfaces between the strips were clear, and the mixture of the melt did not occur. The clad strip could be cold rolled without the annealing. The clad strip did not peel at connecting surface by the cold rolling and continuous bending. The strips were connected strictly. The casting speed was 20m/min, and this speed was much higher than the casting speed of the conventional twin roll caster for aluminum alloys.