Deformation, fracture and effective mechanical properties of sintered ceramics composite under uniaxial compression were studied. To perform this investigation the plain numerical model of ceramics composites based on oxides of zirconium and aluminum with different structural parameters was developed. The model construction was carried out within the frame of particle based method, namely the movable cellular automaton method (MCA). The implementation of the phase transition in the MCA-model composite was carried out on the basis of the phenomenological approach, the main point of which was the formulation of the principle of irreversible mechanical behavior of the material. Increase the fracture toughness of ceramics after (T-M) transition in its structure was realized in the model by introducing transition kinetics of the automata pair from "bound" to an "unbound" state. The structure of model composite was generated on the basis of scanning electron microscope images of micro-sections of real composite. The influence of such structural parameters as geometrical dimensions of layers, inclusions, and their spatial distribution in the sample, volume content of the composite components and their mechanical properties, as well as the amount of zirconium dioxide undergone the phase transformation on the mechanical response were investigated.