In this paper, the effects of melt thermal-rate treatment (MTRT) and modification of Y on the microstructure and mechanical properties of Zn-27Al alloy are discussed. The experimental results suggest that the microstructure can be refined and the mechanical properties can be improved with the MTRT technique. The effect of grain refinement achieves the best when the melt temperature is up to 830°C, the tensile strength of alloy is 452 MPa and the hardness is 123 HB, each measure increasing by 13.6% and 7.1% compared with the untreated alloy, respectively. When the alloy is treated with the MTRT + Y technique, the mechanical properties of the alloys cannot improve compared with that of the alloy treated with MTRT. The mechanism of the effects of MTRT and Y are discussed.