The characteristics of superstructure fiber Bragg gratings (SSFBG) as pulse shaping filters were illustrated. It was interpreted that SSFBG can produce regular rectangle optical pulses in time domain whose optical power spectral density in frequency domain is sinc function. When channel separation was integral times of optical code rate, the neighbor channel presents zero point at the center frequency of signal channel, and the frequency spectrum were orthogonally overlapped. An orthogonal wavelength division multiplexing(OWDM) system based on SSFBG was presented. The system consists of SSFBG in transmitter works as pulse shaper and a narrow band filer in receiver. Mathematic models and simulation results are presented for the ideal narrow pass filter (NPF) and Gaussian filter receiver crosstalk. The simulation results show that both the ideal NPF and Gaussian filter can minimize the inter channel crosstalk. The crosstalk of receiver is weaker than channel crosstalk by about 10 dB when the filter in receiver is narrow enough. The crosstalk of ideal NPF receiver is weaker than Gaussian filter receiver by about 2～5 dB.