Abstract: Protocol-Oblivious Forwarding(POF) is an extension for OpenFlow based SDN architecture. POF switch can handle flows without knowing the forwarding protocols, which provides controller the highest programmability to control the network more flexibly. Because of POF's new mechanism, traditional approach for rule conflict detection in other OpenFlow controller is no more applicable. This paper gives analysis of rule conflict problem in POF and introduce a flow level rule conflict detection method, which based on flow table matching, and implements it in current POF controller. The evaluation shows it fast and accurate.