With the increasing investigation on reliability and stability of engineering structures, it becomes important for reseach on mechanical properties of materials under fracutre conditions. Concerning to fracture problems of large deformation materials, deformation characteristics of the crack tip field is necessarily needed. This paper presents an experimental analysis on a double-cracked rubber disk under the I-II mixed-mode fracture condition. Deformation properties around the crack tip are described through analyzing displacement information acquired by digital moiré method of circular and radial gratings. Also the existence of sector division mode under mixed loading condition is verified, and it is also found experimentally that the shear component makes the sectors shift.