Abstract: Based on the basic equation of metal solidification and cellular automata method, the coupled macro-micro mathematical model of twin-roll casting was set up. The continuous solidification process of Al-10Mg aluminum alloy before the niping point was numerically simulated, and the solidification microstructure, the dendritic grain radius, the dentritic secondary arm spacing were obtained, and the mechanical properties of wedge-strip billet were also predicted. In order to verify the reliability of the simulation results, the metallographic examination and the tensile tests of cast test samples were done. The results show that the gain size, the distribution characteristic of each crystal region, dendrite arm spacing and the yield strengths of cast rolled strip obtained from simulation basically agree with the experimental results.