The emission spectrum for a pair of dipole dipole coupled identical two level atoms interacting with three mode cavity fields resonantly through 6 photon process has been studied. The structure features and physical properties of the spectrum were discussed in detail when the three mode cavity fields are initially in various number states (such as the three mode are all initially in the vaccum field, or in the intensive field, one mode in the vaccum field the other two in the intensive field, and two mode in the vaccum-field the other one in the intensive-field). Then a series of new important properties of the spectra were revaled.