A kinoform with the characters of two-channel was fabricated by adding quadratic phase factors into conjugate frequency spectrum of object.Gerchberg-Saxton(G-S) iterative algorithm was dopted,while keeping the amplitude of frequency spectrum approximately to constant.The phase of the spectrum was quantified into eight levels.An eight-phase-level kinoform was fabricated by using the binary optical technique.The reconstruction images are clear and efficiency of the diffraction is 58.5 %.