Abstract: Cross-range scaling of low-resolution radar is very important to obtain correctly cross-range image and target classification and recognition. According to the technology of in-verse synthetic aperture radar(ISAR), the cross-range scale depends on both radar wavelength and rotating angle of target relative to radar-line-of-sight(RLOS) during the coherent accumu-lation. The former is known while the latter is difficult to determine especially in the case of ISAR. In this paper, a new approach is proposed which is based on the principle of synthetic array and interferometric inverse synthetic aperture. The phase difference of some scatters between two instant cross-range images by two antennae which are placed on one level, can be calculated. The proposed algorithm is applied to the emulational data of two antennae. The theoretical analysis and the processing results show that the proposed method is correct and effective.