This paper introduces the experimental study on the application of ultrafine FeCoCu pre-alloy powder in the matrix of diamond bits. According to the experimental data, with 663Cu contents of 30%, adding FeCoCu pre-alloy powder to the composition of the diamond bit matrix and by adjusting the proportion of FeCoCu powder and WC powder, the hardness of the diamond bit matrix can be effectively adjusted to adapt to different strata. Through the regression analysis, the mathematical relationship between the matrix hardness and FeCoCu contents is obtained, by which, the matrix hardness can be predicted and FeCoCu dosage also can be calculated. The actual drilling tests in field show that the comprehensive performance of the diamond bits matrix with FeCoCu pre-alloy powder is significantly improved, this experimental study provides experiences for further research on wear resistance of diamond bits.