Abstract: Multi-channel SAR can achieve high resolution and wide swath at the same time, which overcoming the inherent limitations of conventional SAR system. Azimuth uniformly sampled data must be reconstructed in imaging procession. A novel method based on fall-rise chirp rate technology is proposed. The original signal is dechirped firstly; then, it is up sampled, and reconstructed by inverse processing of dechirping. Data processing flow is given, and the reconstruction effect of this new method and classical ways using reconstruction filter banks are compared. All simulation results prove the correctness of theoretic analysis.