Abstract: Pt/Ti electrode thin films on Si (100) substrate were prepared by the DC magnetron sputtering at room temperature. Films treated at different temperatures were investigated using X-ray diffraction and atomic force microscopic methods. The effects of annealing temperature on Pt/Ti bilayer bottom electrode stress were dicussed.It is found that a comperssive stress of Pt layer is formed at the initial stage of anealing, so that protruded mounds are formed on the surface of the Pt layer .The thermal stress produced in the annealing process dominates the formaton of the residual stress of Pt layer.Such thermal stress makes the final stress state of Pt layer the tensile stress, and the tensile stress increases with the increase of Pt3Ti intermetallic compounds in the Pt layer.