First the resonant eigenfunctions are obtained by using the Floquet theory. Then the dissociation probabilities are gained by solving the coupled matrix of bound state with continunm state. From the above studies, we have got the decay widths of bound states, the resonant energy positions and dissociation probabilities of bound states. Using the quasi-classical theo-ry and above formulas, we have eonducted some calaulation about decay widths of nonrotat-ing, diatomic molecules in the ground electronic state absorbing one photon or two photons.