FePt alloy thin films with ferromagnetic order and high magnetocrystallien anisotropy (MCA) is one of the most important magnetic material for fabricating as high density magnetic recording media. In this research the FePt thin films were deposited from Fe and Pt targets with 99.99% purity on Si/SiO 2 (001) magnetically soft. This alloy with equal percentages of Fe and Pt possesses the best structure and magnetic properties for goal of fabricating Hard Disk Drive (HDD). This alloy with this structure possess soft ferromagnetic phase and least coercivity. In this statement for using this material as a high density magnetic recording media, we should anneal our sample with different equipments. In this research the KrF excimer laser annealing have been used for annealing thin films. This laser was in the 248nm, first harmonic, ?=1Hz,pulse energy of 120mj , energy density of 4.8mj/cm 2 and voltage of 18KV. We tried to use different laser pulses to find the best pulse with same conditions. The specimens exposed with 3-6-9-12-18-20-40-60-80 and 100 pulses. To determine the energy dispersive of samples confirmed to find the atomic percentage of thin film. After applying different pulses of laser that used for annealing specimens, the samples were used under different test. For investigating the structure properties, the GIXRD used to make reveal the L 10 FePt and ordering parameters. The high ordering of FePt peak reveal in 18 pulses and ordering parameters of 0.91 obtained. For observation of grains boundaries and grain growth of thin films the FESEM used. For determining the roughness of specimens the AFM have been used. For investigating the magnetic properties and studying the single and multiple domains and finding the high anisotropy of the specimens the SQUID test confirmed. The best condition for magnetic properties achieve in 18 pulses with 0.64MA/m.