Abstract: Polycrystalline diamond (PCD) tools have poor thermal toughness, thus less used in interrupted machining with impact. To improve the performance of PCD tools, the substrate was heat-treated to strengthen its bond with PCD and new PCD tools were made to test their life and surface wear after interrupted cutting aluminum alloy. The results indicate that modified substrates have better bond with diamond layer than the normal ones, thus improving the impact toughness of the tools. Tests show that there is no edge breakage on new PCD tools after cutting 128 min, while the wear condition is still acceptable. In conclusion, PCD tools with heat-treated substrate are suitable for interrupted cutting.