Abstract: The superplastic pretreatment processes and superplastic defororation conditions of SiC particle reinforced LY12 alu minum composite produced by stirring casting method were studied.After the pretreatment of homogenizing annealing-hot inverted extrusion-warm rolling-recry-stallization,the SiCp/LY12 Composite exhibites good superplasticity.Under the deformation Condltions of 793K,6.4×10^-4S^-1,the maxium elongation of this material can reach 293%.The effects of SiC particles on the superplastic pretreatment and superplastic deformation were discussed.