In order to shorten processing time for large grain polycrystalline Si thin films prepared by aluminum induced crystallization, the stack of a-Si/SiO2/Al is deposited by radio frequency magnetron sputtering and annealed at two different irregular temperature profiles. The influence of irregular temperature profile on the processing of amorphous silicon prepared by the aluminum induced crystallization is investigated and the condition is discussed under which whether new nucleation appears when the annealing temperature increases. It turns out that the formation of nucleation is governed by the relationship among the grain radium at low temperature, the distance of depletion region, and the distance of adjacent grains.