The invention discloses a configurable network security experiment system based on an SDN. The configurable network security experiment system comprises an experiment management host used for settingexperiment parameters and constructing experiment topology; an SDN controller used for realizing network centralized control, managing the switch and interacting with the database; a simulation host used for realizing link packet loss time delay and virtual network nodes; a system database used for storing topological information and host performance and managing experimental equipment information; wherein the system mirror image is used for providing experimental environment diversity and fusing attack simulation programs. According to the invention, the experiment simulation design based onthe real SDN switch can be realized, the network state can be conveniently monitored in real time, the time delay and the packet loss rate in the network link can be set, and the functions of attack simulation, defense experiment and the like can be carried out.