The electromagnetic vibration table is used as the vibration source, and the effects of vibration frequency, amplitude and time on the segregation structures and mechanical properties of ZL205A alloy cast in sand mold were studied. The results show that with the increase of vibration frequency from 25 Hz to 55 Hz, the proportion of segregation structures decreases firstly and then increases. When the vibration amplitude increases from 1mm to 4mm, the proportion of segregation structures decreases gradually and tends to be stable, and with the increase of vibration time from 30 seconds to 75 seconds, the proportion of segregation structures increases gradually and tends to be stable. The results of hardness analysis show that the hardness decreases firstly and then increases with the increase of amplitude and frequency, and the hardness increases firstly and then decreases with the increase of vibration time. Among the above vibration parameters, the vibration frequency has the most significant effect on the segregation structures and hardness of the alloy, the second is time, and the last is amplitude. Through the research and analysis, the vibration parameters corresponding to the minimum segregation and the maximum hardness can be determined respectively.