Platinum (FePt) is a ferromagnetic material that has a Face Centered Cubic (FCC) crystal structure. FePt material is classified as a hard magnetic material that can be applied as a magnetic storage medium. The composition of the material used in this study was Fe0.85Pt0.15. This study examined the magnetic properties of nano-sphere shaped FePt materials against the coercivity fields under the effect of heat-assisted variations in laser power values. The difference in magnetic properties due to the influence of laser power was seen based on the hysteresis curve. Micro-magnetic simulations were carried out to obtain Curie-temperature values, hysteresis curves, and configuration of the direction of spin of FePt material. This simulation found the Curie-temperature of the material as 650 K. The direction of the magnetization reversed by the power laser-assisted so quickly. With a small coercivity field; magnetic recording media can carry out the writing and recording process in high capacity. Based on the simulation results, laser power that has the potential to be applied to Fe0.85Pt0.15 material. When the computer works at temperatures 0 K, the laser power 0 W to 0.0026 W can be applied. We use the suitable laser power 0 W to 0.016 W at temperatures of 298 K and 318. While the temperature of 339 K cannot be applied with laser power because it gets an overheat temperature.