In view of the technical problem that performance of the drill bit carcass decreases significantly due to the high temperature environment in drilling of deep wells, studies were conducted on the effect of the type of hollow spheres, the number of hollow spheres, and the adding amount of hollow spheres on the mechanical properties of the hot-pressed sintered diamond drill bit at ambient temperature and high temperature. The results showed that the 3540 mesh yttrium-stabilized zirconia hollow spheres were suitable to be added in the matrix of the carcass, and when the addition amount of yttrium-stabilized zirconia hollow spheres was 10%, the overall performance of the carcass reached the best. The impact toughness and flexural strength also reached their maximum values of 3J/cm2 and 903.75MPa, respectively. Addition of an appropriate amount of hollow spheres to the carcass composite will enhance the surface roughness of the carcass, and improve the cutting performance of the diamond carcass and the mechanical properties at high temperatures due to presence of the spherical pore structure.