The four-wave mixing behavior near the zero-dispersion region of the dispersion-shifted fiber is theoretically studied and the case in which several dispersion-shifted fibers with different zero-dispersion wavelengths are combined together for four-wave mixing is considered. The results show that the four-wave mixing in all the dispersion-shifted fibers contributes to the total conversion efficiency, the parametric gain is apparent and the three-dimension efficiency line is very complicated when the signal-pump wavelength separation is small enough.