Abstract: This paper further investigated the characters of the pulsed microwave power ferromagnetic resonance (FMR) absorption in YIG single crystal films under per-pendicular pumping. The single crystal YIG film samples (5.1μm thick and 500μm in diameter) were prepared by the liquid phase epitaxy on gadolinium gallium garnet substrates and photolithographic etching procedures. The pulsed microwave power FMR absorption curves were measured for three different configuration pum-pings at a frequency of 9.18GHz under room temperature. The experimental results show that the main character of the FMR profiles under pulsed microwave powers with low duty cycles is a linewidth broadening effect due to the spin-wave instability processes, and the up-sweep and down-sweep FMR profiles are basically identical. However, the foldover effects of the FMR profiles occur at the high power levels.