As the deployment of wireless multimedia sensor networks (WMSNs) increases sharply, the control granularity of traditional quality of service (QoS) technologies present weak assistance to satisfy the various application requirements. In this paper, we propose a novel architecture of software-defined network (SDN) based content-centric QoS-guaranteed (SCQG) for WMSNs. The SDN is an innovative network paradigm, which has capability to uniformly monitor and control the WMSNs’ infrastructures automatically. In proposed architecture, we formulate proper priority for each content based on its popularity in WMSNs. And also, we extend the SDN controller to match the content and make flow tables each content requests. Besides, we design an k-nearest neighbor (KNN) based machine-learning algorithm to identify the popularity of different contents.