The relationships between the recording properties and the recording laser power and pulse width of the Ag 5In 5Sb 47 Te 33 thin films were investigated and the recording domains morphology was observed. The results showed that the recording domains could be obtained when the recording laser power and pulse width were within a certain range, and the morphology of the recording domains is very clear and is amorphous Ag 5In 5Sb 47 Te 33 . When the laser power and pulse width could not provide efficient energy to induce significant change in the films, the morphology of the recording domains is very illegible. When the ablation took place the recording domains were composed of the ablation area and the surrounding amorphous Ag 5In 5Sb 47 Te 33 . In addition, the optimum recording conditions (12 mW recording power and the 90 ns laser pulse width) were obtained, the reflectivity contrast of the recording domains obtained under the condition is 22% and the domain diameter is 380 nm～400 nm.