Water clouds are considered as the common dispersion systems suspending in the air. In general, droplets can be treated as a transparent dielectric for the laser field. However, once the intensity of laser exceeds the breakdown threshold, laserinduced plasma will be generated in the droplet. This plasma is able to significant influence the propagation of laser field. Since the water clouds are constituted by the countless droplets, it is reasonable to study the interaction between intense laser field and a single droplet as the starting point. The laser-induced plasma is usually generated instantaneously in a micro spatial volume. It is difficult to reveal the detail structure of plasma. We will provide a transient coupling model to study the time-evolution of the laser-induced plasma propagating in a single droplet. Using the above model, we will bring insight into the breakdown threshold firstly. On the other hand, there are abundant features in the both plasma and its coupling laser field. The plasma is initially generated at the location where laser field propagates away from the droplet, if the intensity of the laser is not very high. Meanwhile, after the plasma generates, the droplet becomes opaque. Large amount of laser energy then is deposited in the droplet. The saturation of the energy deposit can be revealed in our model. We would expect this transient coupling model is helpful to estimate the propagation length of the intense laser pulse while it is passing through the water cloud.