Software definition networking is a revolutionary network architecture, which realizes the separation of the control plane and data plane of a network. While providing the centralized controllability and the software programmability, the network itself is encountering many security problems. In order to solve the problem of security threats in SDN networks, there are different layers of unique security challenges and the relevant research on SDN security problems. This paper introduces the depth learning technology into the field of security threat detection in SDN, and propose a security threat detection framework based on depth learning.The framework is based on the research on model establishment, abnormal behavior recognition and decision algorithm design. The software system based on physical memory analysis is under development in SDN. The system verifies the feasibility of this framework, and to finally generate the work plan on SDN infrastructure.