Abstract: In the Fe-Cu and Fe-Cu-Ni matrices, the influence mechanism of adding ultrafine powders (Fe and Cu) on their sintering hardness, stress-strain curve and sintering interface morphology was investigated, and its effect on the performance of diamond core drill bits was studied. Results show that the hardness of the two sintered body can be increased by 6.25% and 12.20% respectively when ultrafine metal powders are applied to Fe-Cu, Fe-Cu-Ni matrix. The service life of the two bits is increased by 21.6% and 82.5% respectively, and the cutting speed of the two bits is slowed by 4.5% and 16.2% respectively. The wear surfaces on the top edges of the bits are fine and smooth, and the friction coefficients between bits and drilling material are. However, the Fe-Cu-Ni matrix prepared by adding ultrafine metal powders has strong wear resistance, which results in significant height decrease of exposed diamonds at the cutting edges.