A new shape contour description method based on eight-direction chain code and Fast Fourier Transform (FFT) is proposed. Firstly, chain code tracks shape boundary sequentially, according to the relationship between contour and chain-code projection-transform value. A constructed chain-code function of contour is transformed using FFT. After optimization, then a new Fourier Constant Factor Descriptor is proposed which is called FCFD. The descriptor is independent of initial point and has rotation, shift and scale (RSS) invariant properties. The results of experiments show that our shape contour description method based on FFT reduces computation and improves the efficiency of data processing effectively.