When the measuring grating is pulled and/or rotated relative to the reference grating, both of the spatial period and the direction of moiré fringes are studied by photonics method in moiré technique, so does the stop of measuring grating. An approach of imaging of two-dimensional object with subwavelength periodic structure is given based on the fact that spatial period of diffractive wave may be larger than measuring grating's one in moiré technique. First, two-dimensional object with subwavelength periodic structure can be encoded by a perpendicular grating so that homogeneous waves can be obtained. Second, passing through the optical system designed specially, the well-distributed waves with evanescent waves can be enlarged so that it can be recognized by CCD camera. Third, the homogeneous waves with evanescent waves can be decoded by a decoding grating. By decoding, the information of encoding grating is filtered, the image of two-dimensional object with subwavelength periodic structure can be reappeared in the image plane. By the approach given, superresolution image of two-dimensional object with subwavelength periodic structure will be obtained. Theoretical analysis and experimental design for the imaging process of two-dimensional object with subwavelength structure are given well by photonics method. At the same time, the directions of filters as well as the main factors of the imaging are discussed in the novel technique.