An electric meter (EM) network system, an EM node and a broadcasting method thereof are provided. The EM node, which is electrically connected to a power supply loop, stores a layer number and a total layer number. When the power supply loop recovers from a power disconnect condition to a power supplying condition, the EM node obtains a waiting time according to a difference value between the layer number and the total layer number, and broadcasts a route message after the waiting time.