The paper studied various morphologies of the quasicrystal phase in Mg-Zn-Y alloys caused by different cooling rates. The cooling rates were reached through five kinds of cooling media. The cooling curves were monitored by multichannel data acquisition cards. A further heat treatment was made to study quasicrystal growth behavior. The results showed that, with the decrease of cooling rate, the quasicrystal morphology changed and its size became larger. Moreover, a planar quasicrystal morphology evolution schematic diagram during quasicrystal growth process was observed for the first time.