According to the coherence theory of F.A. Popp and some experiments, biological photon delayed radiation intensity obeys the hyperbolic function with time. In this paper, the study of garlic ultra-weak luminescence in microwave field shows that not all biological luminescence curves present hyperbolic decay, but some ultraweak bioluminescences are of oscillation trend. In consideration of the interaction between phonon and photon, the result obtained is verified by way of experiment and computer simulation.