Abstract: A new form of Chirp Scaling (CS) algorithm based on Chebyshev polynomials in Synthetic Aperture Radar is proposed in this paper. Instead of Taylor series expansion, the Chebyshev polynomials is used to approximate the two-dimensional frequency spectrum of the received signal which leads to a more accurate spectrum. Then the mathematic model extracted from the optical system is exploited to confirm the scaling function for range cell migration correction. Moreover, the approximation errors have the bounded limitation which improve the focusing effect of edge point and increase the depth of focus of the scene. The results of simulations confirm the effectiveness of the proposed algorithm.