The detector quantum efficiency (DQE) of a linear plastic scintillating fiber (PSF) array coupled with a charge-coupled device (CCD) for hard gamma-ray imaging is studied using a Monte Carlo simulation. The focus is on the energy from a few MeV to about 12 MeV. The excellent characteristic of PSF offers a method to balance the detection efficiency and spatial resolution. Our simulation results indicate that the modulation transfer function (MTF) for different energies become almost the same below the certain frequency and the DQE should be better at lower frequency for imaging lower incident energy. These characteristics suggest that the PSF may be useful for detecting high energy gamma-rays.