In order to get the error-correcting coding information of the unknown lines in digital communication, a fast blind recognition method of Reed-Solomon(RS) coding is presented. RS coding length, the order of the primitive polynomial and the possible primitive polynomials were detected by seeking the roots of binary form of RS codes. The true primitive polynomial and generator polynomial of the unknown line were gained by the position and number of the connective zeros in the Galois Fields Fourier Transform (GFFT) of RS codes using the possible primitive polynomials. The results of experiments and performance analysis show that this method can blind recognize the RS coding of the great mass of unknown lines, and can obviously reduce the number of primitive polynomials searched in the recognition compared with the existing algorithms.