Amplitude/frequency/phase modulation of electromagnetic(EM) wave, as the common way of carrying information, has received intensive attention recently when the wave front acts as EM vortex for information modulation. The progress on the information modulation capability of EM vortex was systematically summarized and its potential on radar information acquisition was also introduced. Aiming at the circular phased array, the echo signal model of ideal point target was established under the illumination of EM vortex wave. Once the echo signal phase of each antenna element was shifted with the same mode as being applied for submission and integrated along the circular path, the output signal of the radar array can be obtained. The output signal can be modeled as the linear superimposition of Fourier basis with the amplitude modulated by squared Bessel function. According to the spectrum characteristic of Bessel function, the approximate dual relationship between the mode number of orbital angular momentum(OAM) and the variable of azimuthal angle was analyzed. Finally, the back projection(BP) algorithm and filtered FFT based algorithm were applied to image the target. Simulations show that electromagnetic vortex wave has the potential to acquire the cross-range profile of the radar target. The research may act as a reference for the design of new mechanism radar and the development of target recognition technology.