Abstract: A multiphase model has been developed and applied to two dimension solidification processing of Al-7 wet pct Si/SiC particles Fgm on different cooling conditions. Solidification processings of no particle, small particle and large particle by cooling on the top, the bottom, side face and four sides are researched. It is approved that there is negative macrosegregation on the field solidified first and positive macrosegregation on the field solidified later. There is macrosegregation of pattern A by cooling on the top and bottom and macrosegregation of pattern V by cooling on the side face and four sides. Scheil equation is approved. The creation of eutectic is affected by species macrosegregation, and the accumulation of large particles restrains the creation of eutectic.