Radar high-resolution range profile(HRRP) has received intensive attention from the radar automatic target recognition(RATR) community.Usually,since the initial phase of a complex HRRP is strongly sensitive to target position variation,which is referred to as the initial phase sensitivity in this paper,only the amplitude informa-tion in the complex HRRP,called the real HRRP in this paper,is used for RATR,whereas the phase information is discarded.However,the remaining phase infor-mation except for initial phases in the complex HRRP also contains valuable target discriminant information.This paper proposes a novel feature extraction method for the complex HRRP.The extracted complex feature vector,referred to as the complex feature vector with difference phases,contains the difference phase in-formation between range cells but no initial phase information in the complex HRRP.According to the scattering center model,the physical mechanism of the proposed complex feature vector is similar to that of the real HRRP,except for reserving some phase information independent of the initial phase in the complex HRRP.The recognition algorithms,frame-template establishment methods and preprocessing methods used in the real HRRP-based RATR can also be applied to the proposed complex feature vector-based RATR.Moreover,the components in the complex feature vector with difference phases approximate to follow Gaussian distribution,which make it simple to perform the statistical recognition by such complex feature vector.The recognition experiments based on measured data show that the pro-posed complex feature vector can obtain better recognition performance than the real HRRP if only the cell interval parameters are properly selected. Radar high-resolution range profile (HRRP) has received intensive attention from the radar automatic target recognition (RATR) community. Usually, since the initial phase of a complex HRRP is strongly sensitive to target position variation, which is referred to as the initial phase sensitivity in this paper, only the amplitude informa- tion in the complex HRRP, called the real HRRP in this paper, is used for RATR, whereas the phase information is discarded. However, the remaining phase infor- mation except for initial phases in the complex HRRP also contains valuable target discriminant information.This paper proposes a novel feature extraction method for the complex HRRP. The extracted complex feature vector, referred to as the complex feature vector with difference phases, contains the difference phase in-formation between range cells but no initial phase information in the complex HRRP. According to the scattering center model, the physical mechanism of the proposed complex feature vector is similar to that of the real HRRP, except for reserving some phase information independent of the initial phase in the complex HRRP. recognition algorithms, frame-template establishment methods and preprocessing methods used in the real HRRP-based RATR can also be applied to the proposed complex feature vector-based RATR.Moreover, the components in the complex feature vector with difference phases approximate to follow Gaussian distribution, which make it simple to perform the statistical recognition by such complex feature vector. The recognition experiments based on measured data show that the pro-posed complex feature vector can obtain better recognition performance than the real HRRP if only the cell interval parameters are properly selected.