That the main invalidation of high-powered engine pistons is thermal fatigue failure has been confirmed through analyzing auto piston invalidation. And a solution has been proposed to use heat-resisting aluminum alloy material in place of conventional piston material ZL109. Comparative trials for both materials have been conducted on their mechanical performances at normal and high temperatures as well as casting properties. The result indicates that they have close room temperature mechanical performance and casting properties. But at 350°C, high temperature performance is raised by 30~40 MPa.