In this study, the effect of crystal formation, grain growth and surface properties on magnetic properties via changed with heat treatment process in amorphous Hitperm-type alloy produced by planar flow casting method was investigated. The produced Fe38Co38Mo8B15Cu1 amorphous ribbons were subjected to selected heat treatments. The low temperature and short time heat-treated samples displayed broad, continuous, and low-intensity XRD diffraction peaks and the intensities of the crystalline peaks increased noticeably with increasing time and temperature. The AFM images of as-quenched Fe38Co38Mo8B15Cu1 ribbon surfaces displayed one type of sharp peak raises evenly distributed on the surfaces. The microstructural of the heat-treated samples exhibited nanocrystalline bcc-FeCo grains randomly dispersed in the remaining amorphous matrix. The mean sizes of grains increased from 1.8 nm to 5.6 nm with increasing heat-treatment temperature and time. The saturation magnetization increased from 81 to 135 emu/g with increasing heat-treatment temperature ranging from 300 to 420 degrees C and then decreased to 113 emu/g for 450 degrees C. The coercivity showed the or non-monotonous dependence with increasing annealing time and temperature.