The cavity-field spectra of a pair coupled two-level atoms in an ideal cavity interacting with two-mode radiation field is studied with the fields both in the binomial state. The influence of the interference effect on the spectra structure is discussed in detail. The result shows that multi-peak structure appears in the cavity-field spectra when the photon number of the two-mode radiation field is equal, the three peaks of each mode spectrum approach ωi and ωi±0.7g and side peaks disappear while the fields' intensity becomes more and more stronger. It's found that when the frequency difference of the initial two mode Δ is larger than 6g (g is the coupling coefficient between the atom and the field) the interference effect of the spectra can be ignored, when Δ is smaller than 6g the interference effect should be considered. Especially when Δ is reduced gradually from 1.4g the three peaks of the mode Ⅰ and mode Ⅱ begin superpositioning, the interference effect is obvious.