Single-layered Fe52Pt48 films with thickness of 10nm were sputter-deposited on glass substrates. Rapid thermal annealing with different heating rates (10–110K/s) was applied to transform as-deposited fcc phase into L10 phase and meanwhile to align [001]-axis of L10 crystal along plane normal direction. Based on X-ray diffractometry using synchrotron radiation source, the texture coefficient of (001)-plane increases with increasing heating rate from 10 to 40K/s, which is correlated with perpendicular magnetic anisotropy and in-plane tensile stress analyzed by asymmetric sin2ψ method. Furthermore, it was revealed by atomic force microscopy that the dewetting process occurred as heating rate was raised up to 80K/s and higher. The change in the microstructure due to stress relaxation leads to the degradation of (001) orientation and magnetic properties. Surface roughness is closely related to the in-plane tensile stress. Enhanced perpendicular magnetic anisotropy and atomically flat surface were achieved for the samples annealed at 40K/s, which may be suitable for further practical applications. This work also suggests a feasible way for surface engineering by controlling internal stress of the FePt without introducing cap layer.