The properties of blue-green laser induced crystallization for as-deposited Ag11In12Sb51Te26 phase change thin films irradiation are studied by measuring the reflectivity contrast at 500, 100 and 60 ns pulse duration. The results show that Ag11In12Sb51Te26 phase change thin films irradiated by blue-green laser have high crystallization speed. The reflectivity contrast of thermal treatment Ag11In12Sb51Te26 phase change thin films is also investigated, and the results show that there is a different in the reflectivity contrast, which is 8% and 19.2%, for laser-induced and thermal treatment films, respectively.