Abstract: According to the solidification model in the spray formed preform, the solidification behavior of typical Al-Cu alloy is calculated and discussed. The result shows that processing parameters such as deposition rate and spray temperature at deposition, and material thermal physical properties such as surface heat transfer coefficient have apparent effects on solidification process in preform. Under the same deposition thermodynamic state just before the spray cone depositing on the surface of the preform, temperature of deposition surface varys significantly as the processing parameters and material thermal physical properties change.