QT600-10 ductile iron is mainly used in core components such as differentials and camshafts. However, with the rapid development of lightweight products, higher requirements have been put forward for the yield ratio of QT600-10. Cu contributes to improving the yield ratio of QT600-10. Nevertheless, under factory production conditions, the upper limit of Cu content is empirically restricted to 0.2%(mass fraction), which severely restricts the tailoring effect of Cu on the yield ratio of as-cast QT600-10. In this paper, the rationality of this empirical parameter was studied by preparing as-cast QT600-10 ductile iron samples with different Cu contents under stable factory production conditions, and analysing the corresponding microstructure, elemental distribution, hardness and tensile properties via various characterization and testing methods. The results show that the empirical limit of 0.2%(mass fraction) Cu is not always rational, for no significantly effect on the microstructures of the as-cast QT600-10 and no harmful phase transitions are found with increasing the Cu content to 0.456%(mass fraction). Meanwhile, the 0.456%(mass fraction) Cu content increases the yield ratio and hardness of the as-cast QT600-10 while maintaining a high total elongation. The findings of this research will provide an experimental basis for optimizing the composition of as-cast QT600-10 ductile iron and controlling the quality of the on-site casting process.