A broadband coupling filter for generating a notch filtering effect is disclosed. In the broadband coupling filter, a substrate includes a first layer, a second layer and a third layer. A first signal terminal, a second signal terminal, and a block transmission line are formed in the first layer, wherein the first signal terminal is used for receiving a signal, and the second signal terminal is used for outputting a filtering result of the signal. A grounding plate is formed in the second layer, having a hole. A third signal terminal, a forth signal terminal and a second block transmission line are formed in the third layer. A connection unit is further formed in the third layer, for connecting the third signal terminal and the forth signal terminal.