Abstract: Defects which was suspected as inclusion were found after rough machining by ultrasonic testing in the ZCuSn10Zn2 centrifugal casting products. The property and reason of the defects were analyzed and judged by means of macroscopic inspection, chemical composition analysis and metallographic examination. The results showed that the property of the defects were structure segregation. The segregation defects were eliminated by heat treatment method, and resulting in the much increase of synthesis mechanical property of the alloy.