The invention relates to an architecture based on fog computing in an SDN (Software Defined Network). The architecture comprises an Internet of Things equipment layer, a fog computing layer, a control node and a cloud computing center. A processing method of the architecture based on the fog computing in the SDN comprises the following steps: step (1), sending a request to the control node by an intelligent sensor via an intelligent Internet of Things gateway; step (2), if not being a delay-sensitive service, turning to step (3), otherwise turning to step (4); step (3), transmitting data to the cloud computing center by the control node, and feeding a result back to a controlled terminal by the cloud computing center; step (4), if a data processing service request is less than a threshold, turning to step (5), otherwise turning to step (6); step (5), searching a server occupancy table and processing the server occupancy table by selected edge servers and feeding the result back to the controlled terminal; and step (6), inquiring the server occupancy table, selecting the edge servers whose CPU utilization rate and memory usage are greater than the threshold by the control node, performing data processing by the plurality of selected edge servers, and returning a processing result to the controlled terminal.