The fractal characteristics of the surface cracks and the damage evolution process of rubber concrete beams under concentrated load are studied. The experimental conclusions show that there exists a quantitative relationship between the fractal dimension and the mechanical properties. The fractal dimension of surface-crack of the rubber concrete beams is able to act as a damage feature index to reflect the damage degree of them effectively. In investigating the crack evolving process of the rubber concrete beams, fractal geometry provides a new technique for the structural health monitoring and the safety evaluation.