Abstract: This paper proposes a new full-aperture imaging algorithm for ScanSAR. Firstly, the two dimensional (2-D) spectrum is obtained by the azimuth pro-filtering which adopts the idea of SPECAN. Then the Nonlinear Chirp Scaling (NCS) method is used to complete the range compression and Range Cell Migration Correction (RCMC). After that, the signal is focused in the Doppler domain by dechirping operation. Finally, geometric distortion correction is carried out via a Chirp-Z Transform (CZT). Without interpolation and coordinate transformation, the algorithm is high in computational efficiency. Both simulation and results of real data are provided to demonstrate the effectiveness of the proposed method.