The performance of optical en/decoder is one of the key factors affecting the whole performance of optical code-division multiple-access (OCDMA) system. Wavelength deviation influences the performance of en/decoder. The wavelength-deviation-tolerance (WDT) of equivalent phase shift superstructure fiber Bragg grating (EPS-SSFBG) encoder/decoder is investigated with different optical codes, different code sizes, different encoding bandwidths, different encoding efficiencies and different refractive index modulation intensities, based on the analysis of EPS-SSFBG as OCDMA encoder/decoder. The result shows that the WDT between optical source and encoder/decoder is relatively moderate, the auto-correlation ratios of PA to the maximum wing lavel (P/W) increases when the center wavelength of source deviates from that of encoder/decoder with wide input pulse width. The WDT is influenced by different optical codes, different frequency efficiencies and different refractive index modulations.