The symmetry of rotation-vibration states of diatomic N2 and O2 are disoribed by means of the chain of subgroups U(4) U(3) O(3) . The transition matrix elements of rotational Raman scattering are calc ulated by means of the group theory approach. The cross section of rotational Raman scattering are given for N2 and O2. The results are in good agreement with the experimental values.