We explore the whole parameter space of the singlet fermionic cold dark matter model with respect to constraints on, first, the relic density and second, gamma-ray lines up to 10 TeV. We investigate 44000 random sample models which comprehensively scan the parameter space for dark matter mass below 10 TeV, and compare our results with the latest experimental data from H.E.S.S., for the first time. It is showed that, except for the resonance regions, this indirect detection cannot exclude the parameter space of this model.