A novel approach to obtain multi-channel comb filters with various channel bandwidths is presented based on a sampled Bragg grating. A kind of high-channel-count comb filter with channel spacings of 50 GHz, 100 GHz and 200 GHz is then fabricated respectively by design of a discrete-chirped sampled Bragg grating structure like a ladder in grating period. This kind of optical fiber filter is characterized by multiple equalized bands with flat-top steep-edge and high transmittance and its inter-channel isolation is more than 28 dB, in-band insertion loss is less than 0.1 dB and phase response is between 5~30 ps in the 3 dB bandwidth. By using proposed approach, the holographic phase mask with discrete-chirped coefficients can be easily prepared in low costs and good repetition. Furthermore, by changing the optical fiber parameters, the optical fiber filters with different channel bandwidths can be implemented in high stability and repetition, which has a good potential in the high-speed optical communication systems and optical interconnects.