Mg72.5Zn26Y1.5 quasicrystal alloys were investigated under different solidification conditions. The specimens of Mg-Zn-Y alloys with cooling rates from 13.2K/s to 69.8K/s were gathered by a designed multi-channel temperature acquiring system and then the microstructures and phase evolution of the alloys were analyzed. The results show that the precipitation temperature of icosahedral quasicrystal phase (I-phase) increased with cooling rate increased from 13.2 K/s to 69.8K/s. The microstructure was mainly made up of α-Mg, I-phase and Mg7Zn3 phase. Meanwhile, the quasi-crystalline morphology was significantly different in the experiments. It changed from five (six) petals to the big pentagon with the decreased cooling rate.