Abstract: Octahedral diamond single crystals with specific {111} plane were synthesized by optimizing catalyst formula, adding new catalyst, designing synthesis process and improving heat preservation chamber. The results of SEM indicate that the diamond crystal is octahedral, and the crystal has regular {111} facet. The results of Raman spectra show that the hybrid type of carbon atoms in diamond crystal is sp³ hybridization state, and that octahedral diamond has higher purity. The magnetic susceptibility test results show that the magnetic susceptibility of the octahedral diamond is lower than 1.00×10^-5 SI. The application results show that dressing tools with this diamond have better sharpness and wear resistance than that with normal diamond.