A328 alloy is an attractive candidate for recycle-friendly aluminum alloy in the recycling of automotive components. In this study, A328 alloy melt was degassed by ultrasonic vibration and the effect of treatment time on the density, fluidity and mechanical properties was investigated. Experimental results reveal that a constant value of density can be reached after less than 180 seconds of ultrasonic treatment time, but the density decreased when the treatment time was 300 seconds. Ti which was dissolved from the horn during ultrasonic treatment reduced the fluidity of melt. After degassing by ultrasonic vibration for 180 seconds, tensile strength increased from 201MPa to 250MPa, and elongation increased from 2.38% to 3.50%, however, further treatment deteriorated the mechanical properties.