The invention provides a process for preparing glass ceramics with a sintering method. The process comprises steps of mixing, pulverizing, compression molding, heating nucleation, cooling crystallization and secondary annealing. The glass ceramics prepared with the method have thick and large crystal nucleuses, high hardness and excellent mechanical properties and are non-transparent, the thickness difference of the glass ceramics is smaller than 0.2 mm, the surface roughness Ra is smaller than 12 nm, rms is smaller than 18 nm, and the breaking strength is higher than 80 MPa and reaches 120 MPa to the maximum. The glass ceramics contain components including Si, Ca, Mg and the like.