Abstract: In response to the problems of poor wettability and low bonding strength between diamond and NiAl matrix, diamond/NiAl composite materials were prepared by combustion synthesis method, using Al powder, Ni powder, and Ti-coated diamond as raw materials. The properties of the combustion synthesized samples are compared with those of uncoated Ti diamond. The effect of Ti-coated diamond on the physical properties, mechanical properties, phase composition and microstructure of combustion synthetic samples were studied. The results show that Ti coated on the surface of diamond is beneficial for improving the density of the combustion synthesized samples. The bulk density is 5.74 g/cm³, the apparent porosity is 14.41%, the Rockwell hardness is 86.1 HRB, and the compressive strength is 160.42 MPa. Ti-coated on the surface of diamond can effectively avoid the direct contact between the high-temperature molten and the diamond, effectively fill and repair the defects of original diamond, and to some extent avoid thermal damage to diamond, resulting in a lower degree of graphitization on the surface of Ti-coated diamond compared with that of Ti-uncoated diamond.