In this paper, according to the geometric characteristics of TiB2 particle acquired from the scanning electron microscopes (SEM), computational structural modeling of TiB2/Cu composites is performed, in which the size, shape, position, volume fraction and proportion of TiB2 particles are numerically reproduced to be similar to those of the actual micro-structures of TiB2/Cu composites. The ductile damage and failure behaviors for matrix, the elastic brittle failure for the particle reinforcement, and the traction-separation for interface, were independently simulated in this model. Four evaluation indexes such as elastic modulus, yield strength, tensile strength and elongation are used to assess the comprehensive mechanical properties of composites. Load-bearing capability of the TiB2/Cu composites is investigated by analyzing the stress and strain distribution of particles, interface and matrix. The validity of the simulation results is verified by the agreement of the experimental stress-strain curve and the morphology of fracture section. The effects of particle size, shape, volume fraction and proportion of TiB2 particles on the mechanical behavior are presented. The present work may provide useful guidelines for optimum composite structures design and industrial applications.