Peking Univ, Dept Phys, Beijing 100871, Peoples R China
; CAS, Inst High Energy Phys, Beijing 100039, Peoples R China
Inflation plays a significant role in interpreting current observations. Despite the success of inflation theory, the reheating energy scale rho(reh) is largely uncertain today. This consequently induces uncertainty to the primordial spectrum when achieving primordial spectra from inflation models. In this paper, we study the effects of this uncertainty on the primordial spectrum and cosmic microwave background (CMB) radiation. For the primordial spectra with small running indices, our result shows that the effect is negligible if the inflation parameter V,, can be normalized freely. But for models with large running indices, we find that rho(reh) can be highly restricted by the CMB observations.