Roll casting of AC4C aluminum alloy was tried using an unequal diameter twin roll caster. This caster was equipped with a lower roll of 1000mm in diameter and an upper roll of 300mm in diameter. A cooling slope was used to make semi solid slurry. The casting speed was 20m/min, and thickness of AC4C strip was 4.5mm. The AC4C strip could be cold rolled down to 1.0mm without homogenization. Rolled and T4 heat treated AC4C strip was not broken in 180 degree bending test (R=0.5), and limiting drawing ratio of 2.0 was obtained.