 Fe3O4 had a cubic spinel structure because of the strongest reflection from 311 planes.  Increasing the pulse laser energy reduces the energy gap of films.  When the pulses laser energy increases, the absorption and the film's thickness increase.In this study, thin films of pure iron oxide (Fe3O4) were prepared using pulsed laser deposition technique under vacuum (2×10 -3 mbar) using Nd: YAG laser at different laser energies (700, 800, 900, and 1000 mJ) on quartz slides at the substrate temperature of 200 °C with different thickness (170, 190, 220, and 250 nm). The prepared thin films were examined using different techniques. The Xray diffraction showed a polycrystalline structure of cubic Fe3O4 phase, enhanced its crystallinity, and increased the crystalline size when increasing the laser energy to 1000 mJ. The results revealed that high transparency samples decreased pulse laser energy. As the laser pulse power increases, the transparency decreases from 91% to 61%, where optical properties deteriorate significantly. The bandgap values were detected to be 3.9 eV, 3.75 eV, 3.21 eV, and 3 eV when the laser energies were increased with thickness (170-250) nm.In addition, the extinction coefficient, dielectric constants, optical constants, and refractive constants were studied.